Abstract: A unitary back-pack air supply to supply air to a pneumatic hand tool. The back-pack includes a substantially flat, rectilinear frame defining an air supply chamber and substantially flat vertical front and rear planes. Shoulder and waist straps are connected with the frame to extend over the shoulders and about the waist of a wearer and to support the frame at the wearer's back. A heat and sound insulating and vibration dampening back engaging panel is carried by the frame at the front plane thereof. A mounting plate is positioned rearward of the rear plane of the frame and is connected thereto by shock mounting devices. An engine driven air compressor unit is mounted on the plate to project rearwardly therefrom. An air supply line connects the unit with the chamber of the frame. An elongate flexible air delivery line connects with and extends between the frame and a pneumatic tool engaged in one hand of the wearer.