N.A. Woodworth Diaphragms Specifications
[The Dovetail Jaw Design includes a unitized diaphragm assembly, self-contained air cylinder, face plate adapter, rotary slip coupling and installation instructions.
The "01" series chucks have stop face capabilities for both center and post style, with the exception of the 13" and 17" sizes. They have post stops only.
Dovetail Diaphragm Assembly Specifications

Double acting chucks, for applications requiring additional chucking pressure, air is introduced ahead of the cylinder through the use of a double rotary coupling to double the clamping pressure.