o ring box 20 years trusty 1.various sizes and good quality 2.NBR,VITON,KFM,SILICON,EPDM 3 O-rings by customer`s drawing o ring box We have NBR o ring kit of(30 sizes, total 382pcs, AS568 standard) , model no: 5A(30sizes, total 382pcs, JIS B 2401 standard) ,model no:5B(30 sizes, total 386pcs, JIS B 2401 standard), model no: 5C(32 sizes, total 407pcs, AS568 standard), model no:8B(32 sizes, total ...