For different kinds of fixed pressurizing or dynamic pressurize occasion,o-rings is an effective and economical pressurize component for deviser. As its low cost and simple use,o-rings are used widely.In common and special occasion,as elasticity material has quite great choice range,o-rings is also used in gaseity medium airproofing. o-rings is vulcanized moulding in mould,and they have circularity section cricoid character. o-rings dimension is decided by their inner pathway and section diameter.