... 3.Trial order welcomed 4.OEM/ODM SBR o ring sealing Materials advice silicone and rubber(EPDM,NBR,SBR,CR,BR,IIR ... zone resistance etc.Technical servicemold design prior to mold making,materials advice and we test samples, then run mass production.Mold ... , strength carton outside,or as your request. SBR o ring sealing