Evernew water bladders are an ultralight, highly durable water storage solution for the weight-shaving fastpacker. Made of layered polyethylene, the bladders are flexible and stand upright when full. Comes with an attached cap and retention cord. Threads are compatible with standard Sawyer water filters. Tolerates cold and warm (<194 deg F) temperatures. Trim some grams from your pack for you next trip to the Evolution basin!