Similar to the MagnaBlock, the Positioning Vise from GRS has one very unique difference: a positionable center of rotation. While working under a microscope, this is an important function that llows the workplace to remain centered in the field of view. This detail saves times while working. As the largest vise made by GRS, the extra weight and a larger base provides the most stability and adjustability available. Includes upper jaw paltes, 5 pins, base, 1 plastic hex key and wrench.