Model # US-5000 is to be used with 5/8? or 3/4? diameter 3- strand synthetic rope lifeline with a minimum tensile strength of 5800 Ib. Polyester type is preferred. Also, the following 5/8? or 3/4? diameter recommended Kemmantle ropes may be used: WARNING! You must read and fully understand all instructions, or have all instructions explained to you before attempting to use this device. Equipment must not be installed, operated or inspected by anyone who does not understand this Owner?s Manual. Failure to observe these instructions could result in serious injury or death. Careless or improper use of this equipment can result in serious injury or death. Training and instruction review should be repeated at regular intervals. If you have any questions regarding these instructions or need additional copies, call: ULTRA-SAFE, INC.1-800-850-5914 DESCRIPTION: The model# US-5000 is a rope grabbing device that follows a worker?s movement up and down a vertical lifeline. If a fall occurs, the rope grab locks on the rope and absorbs much of the force generated during the free fall. The unique energy absorbing design of the US-5000 allows the user to Use a standard rope or web lanyard and still meet OSHA?s maximum force requirements.