The IRWIN Clamp-On Vise can attach to tables up to 2" thick to work almost anywhere. Designed with an anvil shaping horn, it features sturdy pipe jaws with a 2" capacity for general purpose and light-duty work.
From the Manufacturer
The IRWIN 226303 3-Inch Clamp on Vise provides you with the ability to take it with you wherever you go. This forged iron vise has a clamping pressure of 1250-Pound. The IRWIN vise gives you excellent pressure in the convenience of a portable vise.