BLACK+DECKER LST522 20V MAX Lithium 2-Speed String Trimmer/Edger, 12" Part of the 20V MAX System; 1 System - Endless Tasks. Power for your Style Converts from trimmer to wheeled edger Power Drive Transmission for increased torque 2-speed control for more power or extended runtime Automatic Feed Spool (AFS) automatically feeds trimmer line - no bumping required