Sometimes standard FOF indicators don't work in case of darkness or low visibility. That's why lumiscent patches exist.   

Cat eyes are developed for placement at helmet's rear part /backpack/plate-carrier for identification in case of darkness or low visibility.The patch must be attached to the velcro at your gear and equipment.   

This kind of patches doesn't loose form, color and doesn't tear due to the polymeric basis. Use the fabric in different camo patterns, doesn't "shine" In NVG.