Woodys Aluminum Square Support Plates - Red - 5/16in. Thread (24pk.) ASW2-3790 Top-quality backing plates made of lightweight, superstrong aluminum Plates for 7mm studs measure 1 1/8in. square x .125in. thick; plates for 5/16in. studs measure 1 1/4in. square x .165in. thick Available in natural finish and seven colors