Tough and durable fiber glass insert and PU foam. Strongest center thread structure. Different foam layer densities allow Tough and durable fiber glass insert and PU foam.Strongest center thread structure.Different foam layer densities allow you to choose precisely.Excellent resistance to tearing and other damage.Holes:6Face:VelcroFoam layer 11mmThread:5/16"-24UNF3003119 Dia:5" 3003120 Dia:5" ...