4DT’s SECURE Tether System is designed to properly secure your valuable night vision devices. The SECURE Tether system attaches with solid locking mini carabiner style attach points, actually SECURING your NODS. Other bungee systems offer an open hook design, to secure very expensive NODS. In the unfortunate event of you bumping your head and activating the break-away feature of your mount. Rest assured your NODS will be hanging securely by the 4DT SECURE Tether System.