The SL-7D is the newest edger from Silver-Line. This machine was designed without casters to be used on soft woods. The nylon bar on the SL-7D glides along the floor eliminating wheel marks left by standard casters. the SL-7d comes with standard casters for the times you may want to use them. \n\nDue to its unique design, the SL-7D cuts a flatter pattern on the floor. Because this machine is closer to the floor, the dust pick-up is increased and it becomes a dustless edger. \n\nAs with all Silver -Line machines, the SL-7, 110 volt, 220 volt and the SL-7D are hand built and manufactured in the USA for quality assurance and years of low maintenance.