Rubber R6701 fill hoses

Rubber fill hoses have been around for a long time. Each hose is manufactured to set lengths and stamped as R6701 approval and suitable for gas bottles as well as gas tanks that have to have the R6701 approval.
There are lots of hoses options but we do find the straight at one end and 90 degree at the other the most popular.
The fitting on the hoses end is the a 3/4 UNF using a 45 degree seating angle. People refer to JIC as the hose connection which is similar but has a 37 degree seat angle and as such not compatible with our systems.
Rubber fill hoses are lifed at ten years and then must be changed.