I did a little research before buying it. The RV hoses with the green knobs have a hole size which limits the flow of propane in case of a broken line but it does not stop it completely. I saw that firsthand when I had a pigtail go bad last year. The GasStop stops the flow completely. I was worried about a fire while gone or asleep until someone at a show told me of a China Bomb blowing, ripping out their propane hose, and burning up their trailer. There are probably other good reasons to have a flow stop device that I haven't thought of. Kinda like a Boy Scout, I like to Be Prepared!
Don & Julie (and Sophie, our Bichon)
2014 Cedar Creek 34RLSA
2018 F350 CC LWB DRW FX4