CRL offers you a high-quality Rubber Donut for use in making your own glass caddy or rack. They fit snugly over rods or dowels with a 1" (25 mm) diameter. Custom build your own windshield transportation mechanism to fit your specific needs. With CRL Rubber Donuts, you can be sure of safety in glass transportation. Measures 3" (76.2 mm) in diameter by 7/8" (22 mm) thick.