1, Sleeve with oval shape and black color. 2,Each and every pcs was tested at 10kgs/cm2. 3,Inner seal can bear 75 degree. 1, Sleeve with oval shape and black color.2, Each and every pcs was tested at 10kgs/cm2.3,Chipware is zinc.4,Inner seal can bear 75 degree5,The snap spring is stainless steel with heat treatment and the life time is more than 1000 times.