1. High-strength hard plastic lining, light weight, durable, firm and stable 2. Aluminum alloy lock ring, high strength and durable force 3. With waterproof and dustproof PVC plug 4. Material: rubber/sponge, aluminum alloy, hard plastic 5. Diameter: about 22.2mm 6. Length: about 13cm 7. Weight: about 89 grams for the unilateral lock, about 135 grams for the double-sided screw thread, about 96 grams for the double-sided sponge, and about 123 grams for the double-sided skull
