Apple Pie Memories Clear Acrylic ATC Stamping Block 3 in. x 4 in.. Finally, we have acrylic stamping blocks to fit our unmounted ATC stamps. These blocks are from Apple Pie Memories and measure 3 in. X 4 in. which is just the right size for all of your ATC unmounted stamps. They are 1/2 in. thick, laser polished, rounded corners and beveled edges. Make sure you purchase the Tack 'N Peel Cling Sheet or the EZ Mount Foam, so you can use it to mount your unmounted red rubber stamps onto and use over and over.