Prisim Supply's unique polished brass petcock fits direct to a 3/8" NPT female bung on your gas tank. This keeps your gas tank looking very clean. It features a 5/16" diameter hose barb on one end and a fuel filter on the other. Rotating the cylindrical piece with the two grooves is how the fuel is toggled on and off. No reserve.
Many custom and aftermarket gas tanks use a 3/8 NPT petcock. NPT stands for National Pipe Thread, and it is a tapered thread that seals as you tighten the petcock into the threaded fitting on your gas tank.