1. Material: plastic
2. There is a sealing ring inside, dust-proof/leakage-proof
3. The top of the sealing cap, the inner thread is clear
4. Size: large size 19.9x22mm, inner diameter 16.8 mm, small size 18.4x22mm, inner diameter 13.9 mm
5. Weight: large size 4 grams, small size 2 grams