The milwaukee m18tm fueltm hackzall is the fastest cutting and most powerful one-handed reciprocating saw. utilizing a powerstatetm brushless motor and a best in class 7/8" stroke length, the m18tm fueltm hackzall cuts up to 50% faster than competitors. the compact, one-handed design provides superior control and the ability to make cuts in tight spaces. the dual gear counter balance mechanism provides up to 4x lower vibration than traditional reciprocating saws, resulting in faster cut-starts in metal and reduced user fatigue. redlink plustm intelligence ensures optimized performance and protects your investment from overload, overheating, and over-discharge. the m18tm redlithiumtm xc5.0 battery pack provides more work per charge and more work over the life of the pack than competitive batteries.