The inline air line, comes with a macro line fitting already
Knob can come off but you can't lose it.
Ok first off i just got this in and put it on my gun toke about 5 mins. put air to it and it is great! First what i love about is the fact the the airline is in-line witht he ASA, no ebows sticking out making it wider. Second is how easy it is turn on and off. Third How it bleeds whatever air is left in the line so no shooting your gun or busting o-rings. Fourth it come with a macro line fitting already installed!
There is one down side but i feel its noa big issue, You can unscrew the knob and it will come off, but since the airline goes through it you wont have to worry about losing it unless you dont have the air line hooked up, but thats usually when you are working on the gun and not out in the field hopefuly!
I would recommend this to any one looking for a great on/off ASA! and the price is not bad at all.