Knurled Inserts for Soft Materials can be installed into most materials softer than the insert, and which are thicker than 0.062in/1.57mm. During insertion, the threaded nut portion is drawn up into the sleeve portion, providing 360º swaging for exceptional shear strength and pull out resistance, especially in thick fiberglass and plywood's. They are available in Steel and Brass, with 3 finish options. The brass version is particularly useful in the fiberglass boat industry.