The Makita BCS550Z is an 18-Volt LXT Lithium-Ion Cordless 5-3/8-Inch Metal Cutting Saw. The Makita BCS550Z's high torque motor produces 3400 RPM for faster metal cutting. The saw cuts Unistrut all thread, channel, corrugated, conduit, pipe, sheet metal, square tubing, steel and more. The Makita BCS550Z features an ergonomic shape that fits like a glove with even pressure and easy control. The Makita BCS550Z's LXT lithium-Ion provides longer run time, 5x lower self-discharge (for use any time) and 16 firm holding contact terminals (for constant high power) when used with compatible batteries (sold separately). The Rapid optimum charger and battery of the Makita BCS550Z communicates throughout the charging process using the built-in chip in the battery and built-in CPU chip in the charger. The charger also uses Active 3 Control for current control, thermal control and voltage control.