ok, so when my horns are all fitted i want to fit a manual shut off valve tap in the air line inside my car, so at night i can turn off the air supply to the horns for piece of mind,(personal choice) where can i get one of these with the right fittings so i can just cut the pipe and fit one in?
thanks in advance guys… 
i think u can get it at homedepot, lowes…
what about in the uk though… lol ??
any plumbing supply or hardware store should have one what you want is called a ball valve
yup , thats what i had on mine for the night… just a standard ball valve…
You want to look for one that is NPT (national pipe thread)
To put it on the line its just a couple compression fitting or PTC and the valve, put in in the middle with the arrow facing the right way and you have peace of mind!
excellent!! thanks guys thats what i want to do…
If you have trouble finding an NPT one, you can use a BSP vale as long as you can find BSP fittings to fit the 1/2in air line.
i did think that but thanks for confirming it…