1.custom sizes,colors,materials 2.non-toxic,anti-static,waterproof,etc ... 4.breaking elongation:about 200% Colored clear silicone stopper as follows: 1.Material: 100 % silicone rubber2.Hardness:between 20~80 shore A3 ... materials are able to be provided for you,such as silicone,EPDM,SBR,NBR,CR,IIR.,BR,NBR,NR,etc,just ...