A rocket motor with a thrust of 280 pounds-force (1.25 kN or 127 kgf) was chosen. The pack with its fuel weighed 125 lb (57 kg). The pack had a fiberglass frame contoured to fit the operator's body, secured with straps, and cylinders of fuel and nitrogen were attached to the frame. The motor was fastened using a hinged assembly that was controlled by levers under the shoulders while thrust was controlled through a regulator assembly connected to a throttle handle on the right lever of the device. The handle on the left lever governed the slant of the (jetavators) nozzles. Tests of the pack began toward the end of 1960 and were performed in a large hangar with a safety tether. Wendell Moore completed the first 20 tethered takeoffs while making incremental improvements.