Both jaws on this precision vise move in equal and opposite directions so parts of varying size remain centered as long as the vise remains centered to the milling machine spindle. Precision ground dovetailed ways and an adjustable gib provide ultra smooth operation. The jaws measure 4" wide by 1 1/2" high and maximum capacity is also 4". The crank handle measures 4" long and slides on and off when needed. Overall size is 10" long x 8 1/2" wide x 4 1/4" high. Ideal for milling structural tubing of different diameters.