Have watched, with my own eyes, garter snakes simply slither over a fresh barrier of this without little more than a pause. It certainly is not a sure thing. Smells a bit like mothballs so it might keep them away.

IMHO, these clippers seem to be more for kids nails which aren't as strong as adults, or maybe my nails are just very strong. The directions say to soak your fingernails for 30 seconds before using. It warns to dry your nails thoroughly though before using the clippers. After soaking, it worked OK on most of my nails except my thumbnails which are very hard. It requires 2 AA batteries. You turn it on, it has a light to help you see and you stick your nail into a slot on the end which has some kind of rotating blade recessed into it so it's safe. It leaves your nails a little jagged, but if you turn the unit over, it has a filer which smooths the nail. It's a little noisy for such a little unit.