Pro Series Snowmobile Track and ATV Tire Traction Screws 3/8in. Length - 0.190in. Head Height KK038-8-250

I use them in wader boots they are same size as wader boot studs at quarter the cost last longer than most studs for waders too

The media could not be loaded.  If you are a fly fisherman or need grip on your boots, these things are a godsend. Literally the same thing as the $40 screws sold by the fishing companies.