The Levelok Ladder Leveler Can Be Installed On All Type I Rated & Higher Ladders, Kit Includes Two Base Units Which Are Attached To Either Side Of The Ladder. The Included Leveler With A Heavy Duty Swivel Shoe Easily Snaps Into Either Side Of The Ladders Base Units And Can Be Adjusted Up Or Down With A Tap Of Your Shoe Freeing Your Hands To Hold The Ladder While Adjusting Height. Extends Up To A Full 10″, Perfect For Steps. Unit Meets Or Exceeds Requirements For ANSI & OSHA For Safety.