picture of Active Ceramic beer lid total gw: 28g ceramic: 14g airtight ring: 0.8g stainless steel wire: 13.2g specification diameter of s/s wire: 2.8mm ceramic dimension: 25mm(dia.) *22.7mm(H) tolerance: 0.002 Material: stainless steel 430 with chrome, best clay Characteristic: It can bear strong pressure, the endurance can reach to 10Pa, good flexibility, good air-tighness, the circumference can reach to 98%