Model accepts optional 3" (76 mm) diameter Type 27 reinforced Depressed Center Wheels, with 3/8" (10 mm) center hole; wheel width of 1/8" to 1/4" (3 mm to 6 mm). Dual-wick lubrication system saturates gears with oil for increased performance, extended life and reduced downtime. Adjustable wheel guard provides maximum operator protection. Steel housings offer increased durability! Model includes steel right angle housing. Extension design allows longer reach on work-piece, and two-hand control for added comfort.