20V Max Lithium String Trimmer, Gear Drive Transmission Maintains Constant Speed Won't Slow Down During Trimming, Automatic Feeding System Improvements, Minimize Overfeeding, Easier To Load The Spool Adjustable Handle, Includes 1 Each 2.0 Ah Battery, 4 Hour Charger, 12" Swath, For Replacement Battery Use TV #189-554, For Replacement Spool Use TV #722-702.