Vapor Trail Control Cable Mathews MR Series 30 3/8 in.. When the cable is loaded the strands of material within the control cable flex to maintain the original position of the crossbow string. When the crossbow is nocked the string automatically unwinds and the cable reloads the previous strand. When the crossbow is nocked the string unloads the old stinger and trigger cable unloads the new cable. This will eliminate any shock load on the string or cables. Vapor Trail Control Cables have an infinite amount of memory. When you need to quickly pull the string or guide it to a full stop the cable unwinds and the string retracts and the newtongue of the cable returns to fully compress and lock the string into place. Package Contents: Vapor Trail Control Cable Vapor Trail 71387: Control Cable Mathews MR Series 30 3/8 in.