Abstract: A portable self-contained pressure apparatus including a pressurized tank releasably fastened on a backpack carrier for carrying the tank on the back of a user during operation thereof while a handle attachment on the tank and backpack carrier assembly allows them to be manually carried to the point of use. A line pressure control and flexible hose coupling assembly couples the tank pressure to an air pressure responsive load device herein shown as a hand-held spray gun with a feed hopper for applying a texture coating to walls. The line pressure control reduces the tank pressure and affords selective pressure ranges as well as on-off pressure control to the spray gun. The line pressure control and flexible hose coupling assembly are detachable from the pressurized tank when not in use and carried in the feed hopper.