... surface 3. Valve ball and seat materials: stainless steel and tungsten carbide 4. Pump designation: 1) RHAM ... : Stationary Heavy Wall Barrel, Top Anchor, Mechanic Seating, Rod Pump 2) RHBM: Stationary Heavy Wall Barrel, Bottom Anchor ... Thin Wall Barrel, Bottom Anchor, Soft-packed Plunger, Rod Pump 11) THM: Heavy Wall Barrel, Mechanic Seating, ... Barrel, Cup Seating, Tubing Pump API 11AX sucker rod pump