Simpson, 4,500 PSI, Side Assist Replacement Spray Gun, For Cold Water Machines, Designed To Replace Or Upgrade Your Existing Pressure Washer Spray Gun, Equipped With A Trigger Safety Lock Out & Can Be Used With Pressure Washers With Standard Threaded High Pressure Hose & Wand Connections, Ergonomic Design, Easy Pull Trigger Helps Reduce Hand Fatigue For All Day Use, Designed To Fit Most Gas Pressure Washers.