FRAMEABLE SKEEWBACKERSTM - 1/2"
These are classic rectangles and squares. SkeewbackersTM are waterproof, ultra lightweight, clean, and easy to work with. They are constructed from a rigid polystyrene foam core sandwiched between waterproof membranes.
see this short video on SkeewbackerTM
Length & width dimensions may vary by up to 1/8"