The Stabilising Bar is an easy retro-fit for TB Davies EN131 Professional Extension Ladders. If you’re ladder has a notched foot then your ladder can take the stabilising bar. To install, you simply remove the bolts that hold the notched feet, and remove, then attach the stabilising bar and re-attach the bolts, washers and nyloc nuts to lock the bar in place. It is recommended tightening the bolts manually, not with a power tool to avoid unnecessarily crushing the aluminium ladder stiles.