Made from a high quality Butyrate plastic which creates an extremely strong and durable nock. The snap action feature which elimantes “arrow dropping” and is designed to be extremely aerodynamic for better arrow flight. COLORS: Flo Ruby Red, Flo Blue, Flo Green, Flo Orange, Black, White, Flo Pink, Yellow, Green Sizes: 7/32",1/4", 9/32", 5/16", 21/64", 11/32"