This product is designed to allow you to utilize screw-jacks or leveling feet on the ends of truss when used as outriggers on our EF1051 ultimate ballast. These feature several different positions for jacks to be inserted and also feature 3/8" holes on 3" centers for attaching casters. Holes on side of bracket allow for attaching shackles, half couplers, strut channel, etc. for additional bracing options.