Turbo Coil is bigger, stronger, and faster than your average coil. Specifically designed to make binding large books easier, Turbo Coil increases your productivity and profitability when it comes to binding notoriously difficult big books. These binding coils are offered in black, white and clear colors. They are available in sizes ranging from 20mm (3/4") to 50mm (2") in diameter. Bind large books easier and faster with Turbo Coil.