Need a longer hose for your regulator, but don't want to pay the extra cost of ordering up a custom length from your local shop? This adapter is just what you need. Maybe you want to clean your boat bottom or inspect the prop, but don't want the tank on your back. Leave the cylinder on the dock or deck and venture beneath your boat with the freedom of surface supplied air. There are multitudes of uses for a long second-stage hose order a couple now. This Hose Joiner is manufactured from corrosion-resistant marine grade chromed brass.