This Udor RO-70/GR-5 Diaphragm Pump was recently replaced by the Udor ZETA-85/GR-5 (item number ZETA85GR5). However, operators needing a low to medium pressure pump still make a wise choice in selecting this model, boasting a bargain for your money with a 300 PSI maximum pressure and an upper flow limit of 20 GPM. It's specially tooled for use with gas engines ranging between 5 HP and 6.5 HP.