KATSU FIT-BAT Cordless Tools Range they all take the same battery, works on both 18V or 21V, compatible with LXT range, use your current or easy to find on line (compatible with BL1850 BL1860B BL1855 BL1840 BL1830 LXT-400 BL1820B BL1815)With brushless motor, the battery lasts almost twice longer than normal brushed motors, in addition it is maintenance freeRubber soft grip coated handle, takes 115mm and 125mm blades3 speeds controller switch achieves fast and efficient cutting grindingComes with 21V 4.0Ah battery and fast charger, 10pcs 115mm stainless steel grinding discs included Good quality at a very Reasonable price Specification: Brushless motor With 4.0Ah Batteries and charger No-load speed: 3000-9500rpm Three speeds controller: 3000rpm/4500rpm/6000rpm /7500rpm/8500rpm/9500rpm Spindle thread: M14 Blade diameter 115/125mm 10pcs 116mm stainless steel grinding discs included