I use this adapter to blow out my lines on my POPUP Trailer from the city water port using my 12VDC Air Compresssor…
Works great for me...In my smaller foot print case this blows everything down the sink. Then I just add a little pink stuff in the sink trap. If I open the hot water spigot is also blows most of that down the sink as well... Only leaves a small amount of water in the bottom of the water heater... I can also drain from the low water points too first then blow out the lines...
I would get a screw-on adapter for the Air Compressor side if I was using this with the bigger TT trailers...
Roy Ken