Keeping your regulator protected from the elements when it is not connected to a cylinder is important to your safety and the reliability of your Life Support System. Protect your regulator from water, dirt, dust and crawling critters. This non-corrosive Plastic DIN Protector Cap is the kind to ensure proper protection. It slides over the threads of the DIN Connector of your first-stage to protect your regulator from having water enter inside the delicate internal mechanism when washing your gear after diving. Cap comes with a loop of line to attach to regulator, so its right there when you need it.