Orifice 3.5. Minimum Flow Rate: 3 GPM. Minimum Pressure: 3000 PSI. Please check image 4 to choose the size of orifice. If you need orifice 2.5, please order "Tool Daily Pressure Washer Sandblasting Kit, Wet Sandblaster Attachment, 2500 PSI". | The pressure washer sandblasting attachments have a goggle, 10’ hose, 16’’ pressure washer wand (water input), 17’’ sand wand (sand input) and two hose clamps. | Replacment Nozzles are available. Product "Tool Daily Pressure Washer Sandblasting Nozzle, Replacement Wet Sandblaster Attachment, 5000 PSI, 2-Pack". Working pressure of pressure washer sandblaster attachment is up to 5000 PSI. Temperature is up to 140°F/60℃. | Application: pressure washer sandblaster kit works for abrasive cleaning. Great for removing rust, graffiti, paint, baked on grease. | Pressure washer sand blasting attachments use dry silica sand, baking soda or washed and dried river sand.