Oneway Stronghold Jumbo Jaws are designed to re-chuck bowls and plates up to 12" in diameter for complete "bottom finishing." The 8 rubber grippers cushion holds your workpiece during light finish turning and sanding operations. Capacity for the jumbo jaws are as follows: External Chucking 2-3/4" minimum to 10-3/4" maximum. Internal Chucking 4-3/4" minimum to 12" maximum.