When the PASGT helmet system was designed in the late 1970's these elastic bands were standardized during 1981. The primary purpose of the 'Cats eyes' was to avoid friendly fire during the dark hours and also help keep patrols together without the use of torches.
The cats eyes are made from glo-vinyl luminous strips which gain 'charge' from light sources. They can simply absorb light during the day and remain with a slight glow during the night. These bands are elastic so you can simply stretch them out and fit over most military helmets. Another handy feature is by being a simple helmet band, you can add local foliage to aid further concealment.
