3M™ Dual Lock™ Introduction & Buying Guide

3M™ Dual Lock™ is a special type of reusable fastener that connects two surfaces together with a firm “snap.” It uses tiny mushroom-shaped stems that lock into each other, creating a strong, vibration-resistant bond. This system is up to five times stronger than standard hook-and-loop tape (Velcro®) and is designed for both professional and everyday use.

You’ll find it used in automotive panels, electronics, trade show displays, office fixtures, and DIY home projects, anywhere you want a solid connection that can also be taken apart later. Instead of using screws or messy glue, 3M Dual Lock lets you mount, remove, and reattach items cleanly and easily.

Whether you’re an engineer, technician, or DIY hobbyist, Dual Lock helps you make clean, professional installations without tools or visible fasteners. It’s strong, neat, and surprisingly simple to use.

What Is 3M™ Dual Lock™?

3M™ Dual Lock™ is a high-strength, reclosable fastening system that makes attaching materials quick and secure. Unlike Velcro, which uses hooks and loops, Dual Lock features interlocking mushroom-shaped stems made of durable plastic. When two strips are pressed together, the stems “click” and hold tight, forming a firm connection that can be opened and closed many times.

Key Benefits

• Reusable: Can be opened and closed up to 1,000 times.
• Strong hold: Holds up to five times more weight than hook-and-loop.
• Clean and tool-free: No screws, rivets, or drilling needed.
• Durable: Works well in heat, cold, and moisture.
• Versatile: Bonds to metal, glass, plastic, and painted surfaces.

Because it’s both strong and removable, Dual Lock is trusted by engineers, manufacturers, and DIY users who need a simple, reliable way to mount or secure objects without permanent hardware.

The Fastener

When two sides of 3M™ Dual Lock™ are pressed together, hundreds of mushroom-shaped stems interlock. "Snap" announces that the fastener is engaged. Compared to Hook & Loop the tensile strength is greater with 5x more holding power

3M™ Dual Lock™ Stem Count/Mating Chart

Quick Comparison Chart

Type	Stem Count	Strength Level	Best For	Works With
170	170/in²	Easy to open	Light panels, small displays	250 or 400
250	250/in²	Medium	Signs, trims, general use	170, 250, 400
400	400/in²	Very strong	Heavy panels, permanent mounts	170 or 250

Adhesive Guide

	SJ3540SJ3541SJ3542	SJ3550CFSJ3551CFSJ3552CF	SJ3560SJ3561SJ3562	SJ4570SJ4575	SJ4580	SJ3870SJ3871 SJ3872
Bare Metals	X	X	X	X	X	X
Painted Metals	X	X	X	X		X
Fiberglass	X	X	X	X		X
Structural Composites	X	X	X	X
Glass	X	X	X	X	X
Sealed Wood	X	X	X	X	X	X
Powdered Coated Paints	X			X		X
ABS	X	X	X	X	X	X
Acrylic	X	X	X	X	X	X
Polycarbonate	X	X	X	X	X	X
Rigid Vinyl	X	X	X	X	X	X
Plasticized Vinyl		X	X
Polyethylene	X			X		X (Primer Required)
Polypropylene	X			X		X (Primer Required)
Polystyrene	X			X	X
CARC Paint					X
Alkyd Enamel Paint					X
Painted Wood	X				X

*SJ3872 special order

3M™ Dual Lock™ Adhesive Options

Most 3M™ Dual Lock™ fasteners come with a self-adhesive backing, so you can just peel and stick. No screws, no drilling, and no extra glue needed.

But not all adhesives are the same. 3M offers different types to match different surfaces such as smooth, rough, metal, or plastic. Choosing the right one ensures the fastener sticks firmly and lasts for years.

1. Acrylic Adhesive (VHB or 3M SJ3550 Series)

This is the strongest and most durable option.
It’s made for metal, glass, and high-energy plastics like acrylic and ABS.

Best for: Metal, glass, painted surfaces
Use when: You need maximum strength or outdoor performance
Features: Resists heat, cold, and moisture

2. Foam Adhesive (SJ3540 Series)

This one uses a soft foam layer that fills tiny surface gaps.
It’s perfect for rough or uneven surfaces where a flat adhesive might not stick well.

Best for: Textured plastic, wood, or powder-coated surfaces
Use when: You’re mounting on a curved or uneven area
Features: Great initial tack, easy to apply

Clear Adhesive (SJ4570 Series)

Designed for transparent materials and low-profile applications, this clear version is neat and nearly invisible. It’s ideal for when you want a clean look, like on glass, acrylic panels, or signs.

Best for: Glass, clear plastic, display panels
Use when: You need a subtle or hidden mount
Features: Thin, low-profile, and removable

Low Profile:

 

Shop NO Adhesive

 

Shop SJ3440 Type 250, SJ3441 Type 400, SJ3442 Type 170

• No adhesive
• Black stems
• Stem Count Guide/ID

 

Shop SJ3460 Type 250

• No adhesive
• Clear stems
• Stem Count Guide/ID

Quick Adhesive Compatibility Chart

Adhesive Type	Surface Type	Strength	Typical Uses
Acrylic	Metal, glass, smooth plastic	Very strong	Automotive, signage, outdoor panels
Foam	Textured or uneven surfaces	Medium	Wood, powder-coated parts, curves
Clear	Transparent materials	Light to medium	Displays, glass, decor panels

Choosing the Right 3M™ Dual Lock™ for Your Application

If this is your first time using 3M™ Dual Lock™, don’t worry, it’s easy once you understand the basics. The goal is to choose the right strength and adhesive type so your project holds securely, opens cleanly when needed, and lasts a long time.

You only need to think about two things:

1. How strong do you want the connection to be?
2. What kind of surface are you sticking it to?

1. Pick Your Strength Level

3M Dual Lock comes in three strengths: 170, 250, and 400. These numbers tell you how “dense” the mushroom-shaped stems are. The more stems per inch, the tighter the hold.

Here’s a simple guide:

Project Type	Recommended Combo	How It Feels	Why It Works
Lightweight or removable panels	170 + 250	Easy to open	Great for panels you need to remove often
Everyday indoor projects	250 + 250	Firm hold	Strong enough for most uses, reusable
Automotive or vibration-prone areas	250 + 400	Very tight	Stays locked under vibration or movement
Heavy panels or permanent mounting	400 + 400	Hard to open	Feels permanent, nearly impossible to separate

If you’re unsure which to buy, start with Type 250. It’s the most flexible and works for almost everything, from signage to electronics and light construction.

2. Match the Right Adhesive to Your Surface

Each Dual Lock fastener comes with a different adhesive backing. This part determines how well it sticks to your surface.
Choosing the wrong adhesive won’t damage your project, but it might not hold as long as you want.

Surface Type	Best Adhesive	Why It Works Well
Metal, glass, or smooth plastic	Acrylic Adhesive (SJ3550 series)	Very strong and weather-resistant. Great for cars, machines, or outdoor use.
Textured, uneven, or curved surfaces	Foam Adhesive (SJ3540 series)	Soft foam fills gaps and holds tight, even on rough materials like wood or powder-coated metal.
Clear surfaces or display panels	Clear Adhesive (SJ4570 series)	Nearly invisible when applied — perfect for glass, clear plastic, or design displays.

Pro Tip: If you plan to use Dual Lock outdoors or on hot surfaces (like a car dashboard), always choose acrylic adhesive. It handles heat, cold, and moisture best.

3. Real-Life Examples 

Here’s how different people use 3M Dual Lock in real-world projects:

Automotive Use

• Mount a GPS unit, toll tag, or dash camera without drilling holes.
• Attach door panels, trim pieces, or small accessories that may need to come off later.
  
  

Home Projects

• Stick LED strip lights under shelves or cabinets.
• Mount Wi-Fi routers, soundbars, or remotes on walls.
• Create removable access panels for wiring or plumbing.

Office & Retail

• Hang wall signs or displays that can be replaced easily.
• Secure point-of-sale devices or cables neatly on counters.
• Mount acrylic display boxes or panels without visible hardware.

Industrial or Workshop Use

• Hold tool organizers or control boxes on metal frames.
• Attach removable panels to machines or equipment.
• Keep cables and instruments neatly fastened without tape or screws.

In short, Dual Lock works anywhere you’d normally use screws, bolts, or Velcro®, but want a cleaner and reusable option.

Pro Tips for Choosing the Right Combo

• Always pair two compatible types (like 170+250 or 250+400).
• The higher number always increases grip strength.
• For temporary setups, use lower stem counts.
• For permanent installations, go with higher stem counts and acrylic adhesive.
• You can mix types to fine-tune how tight or easy to open the fastener feels.

Shop 3M™ Dual Lock™ Fasteners

When you’re ready to order, choose authentic 3M™ Dual Lock™ for reliable strength and long-lasting performance. Every product listed below is made by 3M, the world leader in industrial adhesives and fastening systems.

You can buy them in bulk rolls, pre-cut strips, or sample trial packs, depending on your project size and budget.

1. Dual Lock™ with Adhesive Backing

The most popular choice for easy, ready-to-use installation.
Just peel, stick, and press.

Available series:

• SJ3540 – Foam adhesive (for rough or uneven surfaces)
• SJ3550 / SJ3551 – Acrylic adhesive (for metal, glass, outdoor use)
• SJ4570 – Clear adhesive (for glass and low-profile mounts)

Perfect for: Signs, electronics, panels, and interior fixtures.

[Order 3M Dual Lock™ with Adhesive]

2. Dual Lock™ Without Adhesive

This version gives you the flexibility to attach using screws, rivets, or specialty glues.
Ideal for projects that need custom mounting methods or high-temperature bonding.

Available series:

• SJ3440 / SJ3460 / SJ3470 (no adhesive)
  
  

Perfect for: Custom assemblies, heat-exposed panels, and flexible bonding setups.

[Shop Dual Lock™ Without Adhesive]

3. Low Profile Series (SJ4570–SJ4580)

The thinner, sleeker version of Dual Lock — strong yet almost invisible.
Designed for display panels, glass, or areas where you want a clean, discreet look.

Perfect for: Retail signage, glass displays, home decor, and removable nameplates.

[Shop Low Profile Dual Lock™]

4. Bulk Rolls & Sample Packs

Need more for your business or testing?
Get bulk rolls for production use or sample packs if you want to experiment before committing.

Available in:

• 1" and 2" width rolls
• 10-foot, 25-foot, and 50-foot lengths
• Pre-cut pieces and trial bags

 [Order Bulk & Sample Packs]

Why Buy Genuine 3M™ Dual Lock™ from Authorized Sellers

When you buy from official distributors, you get:

• Genuine 3M™ performance guarantee
• Full warranty and return policy
• Fresh stock with factory adhesive backing (not aged or degraded)
• Fast U.S. shipping and bulk order discounts

You’ll always receive brand-new, factory-sealed rolls or strips, ensuring the best adhesion and lifespan for your project.

Frequently Asked Questions (FAQ)

1. What’s the difference between 3M™ Dual Lock™ and Velcro®?
   3M™ Dual Lock™ uses interlocking mushroom-shaped stems, while Velcro® uses hooks and loops. Dual Lock is up to five times stronger, lasts longer, and creates a cleaner, more professional bond—perfect for metal, plastic, or glass instead of fabric.
2. Which type of 3M™ Dual Lock™ is the strongest?
   Type 400 is the strongest version, with 400 stems per square inch. It’s designed for heavy-duty or permanent applications, such as large panels or outdoor signs. Pair it with Type 250 for maximum strength that’s still removable.
3. Can 3M™ Dual Lock™ be reused?
   Yes. Dual Lock fasteners can be opened and closed up to 1,000 times without losing grip. To keep performance strong, clean the surface occasionally and avoid bending or damaging the stems when separating.
4. How do I clean 3M™ Dual Lock™ fasteners?
   Use a soft brush or compressed air to remove dust or debris from the stems. Avoid water or solvents, they can weaken the adhesive. Always clean gently to keep the interlocking stems working smoothly.
5. What surfaces work best with 3M™ Dual Lock™ adhesives?
   3M Dual Lock sticks best to clean, smooth, non-porous surfaces like metal, glass, painted panels, and high-energy plastics. For rough or textured materials like wood or powder coating, use a foam adhesive-backed version for better contact.
6. How long does 3M™ Dual Lock™ last?
   When installed correctly, it can last years, even in outdoor or high-temperature conditions. The adhesive stays strong, and the plastic stems don’t wear out like fabric fasteners.
7. Can I use 3M™ Dual Lock™ outdoors?
   Yes. Dual Lock with acrylic adhesive performs well outdoors and resists UV light, rain, and heat. Avoid using foam or clear adhesives in direct sunlight for long periods, they’re best for indoor use.