Bonding on a wide range of materials. The flexible 3M Dual Lock fastener consists of a polyolefin backing with small mushroom-shaped heads that create a stable, yet once-releasable connection when pressed together (audibly). Three densities of mushroom heads can be combined to produce different holding strengths, depending on the need. The SJ387 product family, equipped with a high-performance modified acrylic adhesive, is suitable for bonding on a wide variety of materials, such as high- and low-energy plastics, metals, and many powder coatings.