JL-04 male: 1. Wheel material: nylon2. Wheel tpye: male wheel 3.Metal finished:zinc electroplated4.Packing: 100 pcs per carton JL-04 female: 1. Wheel material: nylon2. Wheel tpye: female wheel 3.Metal finished:zinc electroplated4.Packing: 100 pcs per carton