Grip tight spikes

[numbskull]

Here is a link for grip studs Grip Studs™ Screw-In Tire Studs | Traction in Ice, Snow and Dirt | Wader Studs

There are, however, other options that work well in felt, which apparently holds studs better than rubber.

I think these are popular http://carbidetractionproducts.com/i...id=5&Itemid=27

I've also used wearbars studs with some success in vibram boots, but I think the INS product above is supposed to be better.

Simms also makes some low profile studs that lots of fly shops carry.

What length to get depends on what you do. Lots of bubble weed you want long ones. Slippery bare rock you want short ones.