Use this under your multifunction set for a solid firm foundation when on a level surface. Has a hole at 2.5 inches to accept most types of scaffolding. Can be used in conjunction with a caster jack which allows good versatility. You can order the caster jack for use with casters or take the caster out and use the base plate to form a level jack for a stationary application. Comes Galvanized. Weight 1.5 lbs each. For use with #6 tube size only.