Permanent Installation Includes All Connecting Brackets And Hardware Needed To Connect One Scissor Jack To Frame Made In U.S.A. Automatically Moves Into Place When Jacks Are Lowered No T-Handles, Twist Locks, Thumb Screws, Or Other Locking Devices Needed Greatly Reduces Side-To-Side Movement In The Trailer Attaches To All Scissor Jacks, Except BAL Low Profile Can Be Attached From A Scissor Jack To Frame On Any One Of The Four Corners Of Trailer