Puyang Zhongshi is manufacturer of bow spring centralizers,rigid casing centralizers,float collar,float shoe,cement plug,cement basket,stage collar,sucker rod pump,sucker rod pump valve ball&seat,sucker rop pump barrel&plunger,API pump unit&pump jack,sucker rod&coupling,sucker rod guide,casing &tubing coupling,casing&tubing&pup joint with API 5CT ,API 10D,API 11E and API 11AX Certificate in China.