Biswing Pressure Washer Pump, 1″ Shaft Horizontal Triplex Plunger, 4400 PSI Max, by | Jul 24, 2026Manufacturer Biswing. Biswing 1″ Shaft Horizontal Pressure Washer Pump. (ONLY Fit 1″ Shaft Horizontal Engines). Only suitable for COLD WATER use. Orientation Horizontal. ONLY Fit 1″ Shaft Horizontal Engines.