... type,it can be divided into three types including stationary barrel bottom fixing rod pump,stationary barrel top fixing rod pump ... 250RSB30-250RST Notes: 1. Type of barrel: chrome plated or carbonitrided surface 2. Type of plunger: metal spray or ... Plunger, Rod Pump 11) THM: Heavy Wall Barrel, Mechanic Seating, Tubing Pump 12) THC: Heavy Wall Barrel, Cup Seating, Tubing Pump API 11AX sucker rod pump