... for bottle stopper: Material: 100% silicone rubber Shape: Accordint to your blueprint OEM silicone rubber gasket for bottle stopper: 1, Material:NBR,CR ... ,HNBR,ACM, SBR,EPDM,IIR,NR, EP,SIL,FKM etc.2, Hardness ... :Between 30~90 shore A3, Property: high/low temperature resistance,oil and fuel resistance, ...