Part of Closed's outerwear is created at Donglong in China, mainly jackets lined with Thinsulate™ Featherless by 3M™. This material is an innovative down alternative that Closed has been using since 2015. Donglong has invested a lot of time and know-how in working with 3M™ to develop the appropriate filling technology. The technical materials that Donglong processes are produced in China, keeping transport routes short.