US Patent 7222695 Ladder leveller

A ladder leveller for mounting onto at least one stile of a hollow runged ladder includes an elongate stile extension member, a cross bar sized for mounting journalled through a hollow rung of the ladder. A locking pin extends from the cross bar, through one of an array of apertures in the extension member and cooperates with a locking bar. The locking bar is releasably mounted onto the locking pin to lock the stile extension member onto the stile.