The Astro Tool 498K 0.498" Shank "THOR" Air Hammer / Riveter is the most powerful automotive air hammer on the planet that requires a 3/8” airline, 6.2CFM, suggested use with HI-FLO fittings. This tool accepts .498" shank size bits and most quick change chucks, manufacturer is not responsible for resulting broken air hammer bits. The 498K is not for casual use, always wear ear and eye protection. Specification: Air inlet: 1/4" Working pressure: 90PSI Free Speed : 1140 BPM Piston Dia. : 19 mm / 3/4" Piston Stroke : 98.4 mm / 3-7/8" Shank Dia. :12.6 mm / 0.498" Air consumption: 6.2 CFM Vibration value: 22.52 m/s2 Sound power: 94.4 dBA Weight: 2.5 kg / 5. 5lbs Overall length: 257mm / 10"