3,000 Blows per minute for fast cutting action xxxxxxx High performance and low weight Multi-patented muffler/exhaust system gives this tool and extremely low noise level of (88 dBA) and vibration level of 4.2 m/sec2 5100-A-T and 5100-A includes heavy duty ball-lock quick change chisel retainer adding safety and reliability Model 5100-A Includes: Blow Mold Kit, 5 Pc. Chisel Set and Quick Change Retainer