The Gen 3 Level 4 is part of the Extended Cold Weather Clothing System (ECWCS).
  
The level 4 is a dual purpose low volume shell layer.  It can be worn as a wind proofing barrier layer over insulative layers in cold conditions.  It also features a moisture-wicking design so that it can be worn in moderate to hot conditions next-to-skin under heavy gear as a sand and dust barrier.  Combined with its low weight and volume, it is ideal for anyone in unpredictable or changing weather conditions.

Features:
Two Chest and Two Shoulder Pockets
Loop Side Velcro for Name, Rank, and Unit Patches
Elastic Wrist Cuffs, Full Zippered Design, IR IFF Shoulder Tabs