This line of cut-off saws incorporates a durable, rugged design and a unique three-stage air filter system that enable longer service life and less downtime. A high-torque 5.8-hp engine combined with low machine vibration enable optimized cutting performance. The vibration damping system cuts hand-arm vibration to less than 5 m/s2. The 24-lb. BTS 630 has a 12-in. blade diameter with .08-in. arbor, while the 24.5-lb. BTS 635 has a 14-in. blade diameter and 1-in. arbor. The 24.9-lb. BTS 635S offers a soft start option, which includes a spring system that supports the starter mechanism and reduces the effort required to pull the starter rope.