Here's what other sites are saying:
The Petzl Huit is a figure-eight descender for descending on single or double rope.
Sometimes those long descents can really heat up a descender, the Petzl Figure 8 (huit antibrulure) has an anti-burn grip for holding the device when it gets hot.
Petzl Huit Descender FEATURES of the Petzl Huit Descender Square shape to reduce kinking the ropes and formation of a lark's head knot Compact and lightweight The SPECS of the Petzl Huit Descender Weight: 100 g Rope Compatibility: For use with ropes between 8 and 13 mm in diameter Aluminum Case Quantity: 15 ALL CLIMBING SALES ARE FINAL.
The Petzl Huits figure 8 square design reduces twisting of the rope and risk of girth hitch formation while rappeling.