The Redline HPA hose is a great, reliable braided hose with two QD connectors. This makes it easier to attach to your engine hose. Once the nipple is connected, it stays sealed and tight so tugs will not break or loosen the hose. They also feature a replacement nipple for your HPA engine in case one gets lost. They are compatible with all HPA systems so there is no guessing game on what will work. Be sure to pick up yours at Airsoft Megastore while they are in stock!