This is just what you need for your RV that has a hookup for a dual propane tank. The primary cylinder has a capacity of 210,000 BTU/hr and the reserve cylinder has a capacity of 130,000 BTU/hr.
You will enjoy a constant gas pressure as the regulator will automatically change from an empty tank to a new one. Then you can replace the empty tank and, when needed, it will swap back.
Because there is a double stage design, it will allow you to have a constant gas pressure even when the demand for gas fluctuates. The inlet is a ¼ inch SAE inverted flare whilst the outlet is a 3/8 inch Female National Pipe Thread.