as move his hand and change the displacement of the mantle specifically to increase speed of descent the user relaxes his grip on the mantle 155 so as to allow the volume of the mantle adjacent his hands to grow close to its original pre compressive size to decrease speed the user tightens his grip on the rope 10 thus compressing the mantle 155 the compression of the mantle 155 absorbs energy as any spring absorbs energy this energy is now removed from the kinetic energy balance of the user and transferred into the rope importantly the energy does not like conventional fast ropes manifest itself in the form of heat energy at the rope user body interface thereby avoiding the burn hazard encountered with conventional fast ropes as the user slides down the rope the user 39 s contact points along the rope 10 and the rope 39 s sheath 160 also generate dynamic friction the polymeric coating of the sheath 160 of the present invention allows for more friction than conventional rope fibers but allows free but secure sliding along the rope 10 when the user 39 s grip is relaxed this increase in friction allows for more of a reserve in braking ability permitting the user.