With a massive 4-1/2" diameter body, the Stronghold chuck is perfect for heavy turnings that require maximum stability and gripping power. It's key-operated, so one-handed adjustments are simple and fast. A 5/1 ratio ensures solid holding power, while the patented over-extension prevention system ensures that the base jaws will never come loose during operation. A wide range of accessory jaws are available to cover all your turning requirements. The #3 Jaws have the mass and size necessary for large bowls and vases. The profiled jaws provide maximum gripping power with minimal damage to the piece. Spigot Jaws are machined long and deep for a better grip on smaller parts. Both outside and inside surfaces of the jaws are serrated to grip the work piece. The Jumbo and Mega-Jumbo Jaws are solid machined aluminum plates. Their unique combination of slots and tapped holes accept rubber grippers for holding an infinite number of round, oval or square shapes.