The Rollgliss™ Fisk Descender™ is made from 304 stainless steel, its one-piece design offers gentle flow for 19 inches of working line to pass through the descender over a larger radius found in other products on the market. This design offers less wear to the working line, reduction in rope hockling, and torsional twist. The 304 stainless steel was chosen because of its durability and greater thermal capacity over other materials (ie. aluminum), thus reducing the temperature increase of the unit during a descent. Basic training procedures are combined with the purchase of our DVD video; it is designed to offer assistance in training the user for various techniques used in descending.