DMM Revolver Wire Carabiner
The I-Beam construction lightens this carabiner substantially so the benefits of reduced friction from the roller weren't compromised by the biner being too heavy. Other important factors to consider: Since the rope rolls over the roller there's less wear and tear, which will increase the rope's working life. Also, by reducing friction when a climber falls, system forces are more evenly distributed, resulting in less force inflicted on the last piece of pro. The Revolver also offers options in terms of rigging hauling systems or improvised rescue since it works just like a small pulley.
The roller is made of 7075 and blends smoothly into the back of the carabiner to encourage the rope to run correctly. Inside the roller is a dry tube Igus bearing that is supported by a high tensile stainless sleeve over a high tensile stainless spindle. The whole assembly runs smoothly, and the spindle will not deform until a force approaching 10 to 12 kN is generated.