Check the listing for details. OPS CORE TAN ACH IMPROVED H-NAPE RETENTION SYSTEM HELMET EXTENSION NEW. Condition: New. Listed at 25.00 USD. This OPS CORE TAN ACH IMPROVED H-NAPE RETENTION SYSTEM HELMET EXTENSION is a high-quality accessory that is perfect for military enthusiasts. The product is an original and branded with ARC. It is a new product that has not been modified and was manufactured in China. The theme of this product is Militaria and it falls under the categories of Hats & Helmets, Original Items, Current Militaria (2001-Now), and Collectibles. The Time Period Manufactured is 2001-Now. Additionally, it comes with an H-nape retention system that is guaranteed to keep your helmet secure.