Six Jet 70431-2, 31-Inch Parallel Woodworking Clamps
Professional-grade woodworking clamps:
*Exact 90 degree clamping at up to 1,000 lbs. pressure
*Built-in ruler for a consistent setup and quick identification of opened capacity
*Ergonomic handle with soft grip for comfort and increased torque
*Moveable rail stand/end stop to preset clamping capacity rapidly and accurately
*Non-marring, glue-resistant jaw faces
*Reversible clamping movable jaw can be reversed to be used as a spreader
Barely used, these cost 6*72=432 new: https://jettools.com/70431
These have always stayed indoors in a dry space.