... 3 Reliable & long life 4 Convenient operation and maintenanc API M Front-mounted pumping unit adopts crank-balance. The special structure ... mechanical wear and lower noise. NO.ModelRated polished rod capacity (lb)Stroke(in)Rated torque of reducer(lbf·in)1M-912D ... ,68228,0009M-160D-173-8617,30086,72,58160,000 API M Front-mounted pumping unit