For use on all aluminum extension ladders of all duty ratings with rails up to 3-5/16" x 1-3/16". Attaches in minutes. Mar-resistant rubber caps protect work surfaces. Comes complete with paint can hook, mounting hardware, and instructions. Span: 48". Standoff: 10", ideal for stabilizing Werner's Multi-Master model No. MI and M2 ladders when in scaffold or stairway postitions. Made of alumimum.