Steel swivel shoes. Easily locks and levels. Up to 8-1/2 in of adjustment. Heavy duty construction. Attaches to ladders side rails with locking nuts and bolts. Width of ladder and leveler is 3-1/4 in wider than ladder. Fits aluminum series No. D1100, No. D1200, No. D1300, No. D1500, and No. D500. Fiberglass series No. D5900, No. D6000-2, No. D6200-2, No. 7100, No. D7100, and D7500. Two Level-Master Ladder Levelers (one for each side of ladder), mounting hardware and instructions included. U.L. Listed and Labeled. Meets OSHA Standards.