Sears Self-Squaring Frame Clamp. Tightens all four corner joints equally and simultaneously with just the turn of a central wing nut. Jaws leave joints visible for inspection and easily adjust to accommodate frames from 5" x 7" to 26" x 30". Made of aluminum with plastic jaws. Folds to 21" long. $30 Cash Only. Please include your phone number in response. I'll remove the ad as soon as it's sold. Will only meet in public place. Thanks