4 sizes, made with a double sides, recycled fleece, and double sided velcro so they stay on. Mulvey likes to go swimming in show banks and when he comes out still wearing all the booties, I have done my job. All 4 sizes are reinforced at the toe and pad with Slip-Not, a rubberized fabric that is soft enough for Fido to grip through but keeps his toenails from poking through. It is said to be flexible to 40 below zero. I've tested it at 20 below but I don't go out if it's any colder than that. If you do, let me know how it works out.
Small-paw width up to 2 inches
Medium-paw width up to 3 inches
Large-paw width up to 4 1/4 inches
XL-paws like a Sasquatch (XL size is sold out for the 2022-2023 season, which is why you can't find them as an option.  Try AK Bark in Anchorage, they still had some the last time I spoke with them.)