3M™ Dual Lock™ Reclosable Fastener SJ3552CF, Black, 6 in x 50 yd, Type 170, 1 Roll/Case. 3M™ Dual Lock™ Reclosable Fastener SJ3552CF is a convenient 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) which bonds to a variety of substrates including metals and plastics such as acrylics, polycarbonate and ABS.