A capstan operated wedge grip where the body moves upward under the capstan action, closing the jaws on to the sample. This action minimises the pre-load applied to the sample by the grips. The jaws are sprung loaded to the capstan rod, this eliminates backlash and allows the jaws to move when load is applied.

Various jaw sets are available as shown above, special sets are available on request. Flat faces utilise a pyramid tooth form of 1mm pitch, round faces used a buttressed tooth of 1.25 or 2 mm pitch.