1,Good aging reisistance. 2,Economic price. 3,Good elasticity. Auto moulded rubber bellow : Name Auto moulded rubber bellow MaterialNR,SILICONE,EPDM,SBR,NBR ... ,CR,BR,IIR etc SizeOptional AdvantageAbundant experience,high quality but competitive price ... want to more information ,please feel free to contact me. Auto moulded rubber bellow