This is the Zeagle Octo-Z hose fitting, install into any 3/8" regulator The standard Octo-Z hose fitting is a threaded attachment installed into a standard 3/8" regulator hose. You can use this fitting to create an Octo-Z hose of any length by screwing it into any 3/8" regulator hose. This is the same fitting you&';ll find in your Octo-Z&';s hose installed by Zeagle. "