... Flexibility strong 3:stand strong collision 4:customized 5: diaphram with rubber,long lifetime Features: MaterialNBR,HNBR, MVQ, NR, EPDM ... 's requirements (eg. Tensile strength, elongation, compression set, high temperature resistance, low temperature resistance, ozone resistance... )Color black ... mold center, can develop most kinds of high tech required molds. Black rubber diaphragm with good quality