Has anyone found a cheap knob to fit their regulator?

[SpeedYellow]

My regulator, like so many others, didn't come with a knob, and I'm tired of looking for a screwdriver every time I want to make an adjustment. Surely there's something cheap out there, no?

My regulator's shaft is threaded and has a nut, so I'd assume it's intended to have a knob.

 

[Onkel_Udo]

Why not just find a wingnut with the same thread pitch?

Edit: Probably need to be more clear in my answer. What I intepretted above is that you have a threaded stud with a slot in the end for your regulator adjustment. If this is the case you actually need two nuts and a wing nut. First nut goes on, then wing nut then second nut. Second nut stays flush with the end of the stud and it hel with a wrench while first nut is "jambed" to the bottm of the wing nut.