The material of bottle cap is PP and PE.
The caps are in different sizes, such as 28mm, 30mm, 38mm, 45mm and 55mm, for jars, bottles, containers, drums, and so on.

The Opening torque of hot-filling bottle cap: 10-16 lbf.in, The mineral water bottle cap: 6-14 lbf.in.

Sealing test: keep caps under 700Kpa one minute, then check the cap leak situation.