Permanent hydrant adapters to convert NH/NST threaded hydrants to storz connections. Includes set screws for security, cap and chain. The most common conversion in from a 4 1/2" NH threaded hydrant to a 5" storz connection. Please check or measure your current hydrant carefully. NH size is measurement in the inside diameter of the male outlet of the hydrant. Storz connections on your LDH supply hose should be marked with size.