3M™ Dual Lock™ Reclosable Fastener SJ3440
Black, interlocking mushroom-shaped heads (250 stem density per square inch) provide strong, reliable and durable fastening that can be opened and closed multiple times
Mates with Type 170, Type 250 or Type 400 stem densities to provide different strength combinations
Non-adhesive back for attachment with hot melt, epoxy or liquid adhesives
Strong fastener secures with an audible snap, verifying closure
An alternative to screws and bolts, this hidden fastener provides a snug fit and smooth aesthetic appearance
Features good temperature resistance of 220°F (104°C), though temperature resistance may change based on adhesive used
Suited for indoor or outdoor use
3M™ Dual Lock™ Reclosable Fastener SJ3440 is the easy and clear alternative to traditional fastening methods, such as screws, nuts or bolts. It is designed to deliver a durable, reclosable fastening solution, which can be opened and closed multiple times. This black fastener is most commonly attached by applying hot melt, epoxy or liquid adhesive.
3M™ Dual Lock™ Reclosable Fasteners are available in three stem densities to customize for the strength requirements of your projectUnlock Simplicity
Durable and secure, 3M™ Dual Lock™ Reclosable Fastener SJ3440 has exceptional strength through its interlocking mushroom-shaped heads (250 stem density per square inch). With 3M™ Dual Lock™ Reclosable Fastener SJ3440, there is no need for any drilling or screwing. This fastener is most commonly attached by applying hot melt, epoxy or liquid adhesive.
Recommended Applications:
Design Flexibility
3M™ Dual Lock™ Reclosable Fastener SJ3440 consists of interlocking mushroom-shaped heads that easily slide over each other, allowing for positioning of parts before being snapped together. This fastening process creates a durable attachment and provides fast product assembly with great design flexibility. Our reclosable fasteners can also engage with different stem densities for varying levels of strength and system performance.
3M™ Dual Lock™ Reclosable Fasteners sound an audible snap when secure, which verifies closure of the attachment. To disengage, simply peel the pieces apart by hand. Our fasteners maintain their strength throughout multiple attachments and detachments. A lightweight alternative to metal fasteners, this product remains hidden beneath surfaces and does not interfere with the integrity of your material—providing aesthetic improvements and design flexibility.











