Shake the pump several times before installation to prevent the internal steel ball from sticking to the alloy plate, which may cause the product to malfunction Professional installation is highly recommended. Replacement pump model 246428/246-428/17J552, designed for airless spraying machines 246428 246-428 17J552 Airless Pump, Replacement for Ultra Max II 390, 395, 490, 495, 595, and LineLazer 3400 sprayers.(Not compatible with for Max 395/495/595 and PC Por sprayers) Made of high-quality stainless steel, more cost-effective than the Endurance pump; each pump is performance tested with hydraulic oil be quality checked before sending to you.We never want to make our valued customers disappointed., Weight: 2.97844515962 Pounds, Manufacturer: Ehwisbe