1/4" Turbojet hose Attachment.
PLEASE NOTE: this isn't an attachment that is used on a pressure washer, it's used in lieu of a pressure washer. When attached to the hose it produces more pressure than a regular sprayer nozzle, but not as much as a pressure washer. It can clean concrete of mild funk, but is not capable of serious funk.
Think Jamiroquai,not Bootsy.