0.25" Pump: P0.25 0.5" Pump: P1, T1, P100 Advanced 1" Pump: P2, T2, P200 Advanced 1.5" Pump: P4, T4, W4, P400 Advanced 2" Pump: P8, T8, W8, P800 Advanced 3" Pump: P15, T15, W15, P1500 Advanced 4" Pump: T20
P Series = Proflo - Anti Stall. T Series = Turboflo W Series = Wilflo - High Performance Advanced = Bolted Series