This is the genuine RFI Issue gear being issued to US troops. Constructed with Polartec grid material, this layer provides extra warmth in cooler conditions but still wicks moisture away and dries fast. The material offers stretch for increased comfort and is lighter weight with less bulk than previous systems. Highly breathable, fast-drying next-to-skin layer. Moisture wicking for evaporative cooling in mild climates. Reduced chaffing and increased comfort during movement. NSN numbers include 8415016411816, 8415015460160, 8415016411818, 8415015388598, 8415016411819, 8415015388614, 8415016411824 and 8415015388705.