The helmet shock cord kit will provide additional stability to night vision devices. It easily slides into the upper T-slot of the EXFIL® Rail 2.0 or the quick release mounting slot on the EXFIL® Rail 3.0 – allowing quick and easy attachment and removal. The length is adjusted by simply knotting at the desired size. The included harsh-weather rated zip ties can be used in the event the plastic hooks do not fit your night vision device.