If you want the thick, luxurious soap found at professional car washes, look no further than Kärcher's Foaming Soap Applicator. Simply add detergent concentrate to the canister and top with water. This accessory turns your pressure washer into a personal car wash! Connects directly to the spray gun on select Kärcher electric and gas (up to 4000 psi) pressure washers. Compatible with most brands of Quick Connect-equipped pressure washers rated to 4000 psi.