3M SJ-3550CF Dual Lock Reclosable Fastener, mushroom-shaped, black (various sizes)

3M™ Dual Lock™ SJ3550CF is a black industrial mushroom-head fastener, designed as a durable alternative to traditional fastening methods such as screws, bolts, or snaps. Thanks to the interlocking mushroom-head technology (density of 250 stems/in²), it provides an extremely strong, yet repeatedly openable and reclosable connection. The fastener is equipped with a clear acrylic tape, which ensures excellent adhesion to various materials such as metal, glass, acrylic, ABS, and polycarbonate.

Technical Specification

• Type: Industrial mushroom-head fastener (Type 250)
• Color: Black
• Width: 12.5 mm, 25 mm
• Length: 1 m, 5 m or 45.7 m
• Thickness: 5.7 mm
• Stem Density: 40/cm² (250/in²)
• Adhesive: Acrylic, clear
• Operating Temperature: up to 104°C
• Application: Indoor and outdoor

Application

• Mounting panels and technical covers
• Fastening nameplates and electronic components
• Installation of advertising materials and decorative elements
• Temporary and permanent structural connections
• Mounting equipment in vehicles and industrial devices

Benefits and Features

✅ Strong and reusable connection – provides hundreds of open and close cycles
✅ Quick application – no drilling, screwing, or welding required
✅ Excellent adhesion – to a wide range of substrates, including plastics and metals
✅ Resistance to external conditions – UV radiation, moisture, and chemical substances
✅ Aesthetics – invisible mounting does not disturb the appearance of the surface
✅ Mounting confirmation – characteristic "click" sound when closed

Usage Tips

Before application, the surface should be thoroughly cleaned and degreased. Peel off the protective liner and firmly press the fastener onto the substrate. For full bonding strength, it is recommended to wait 24 hours. Connect the fasteners by pressing them until a characteristic "snap" is heard. To disconnect, simply peel the elements apart gently. The product can be combined with other Dual Lock™ versions of different densities, depending on the application needs.