3M™ Dual Lock™ SJ3550 has mushroom shaped heads that snap together. This product is a “Type 250” which means it has approximately 250 stems per square inch. It will “mate” to itself and other Type 250, Type 170 and Type 400 3M™ Dual Lock™ fasteners. When mating to Type 170 there will be less of a grip, while mating to Type 400 will provide a tighter grip. Most applications will work using just Type 250 alone and has the added ease of only having to keep track of one type of Dual Lock. SJ3550 can be identified by black stems with a plain white adhesive backing. The adhesive is acrylic should stick to most plastics and has a wide temperature range which makes it a good choice to use outdoors. If you require these similar characteristics in clear or with extra UV resistance, SJ3560 in the related items below is also an option.