After owning several pairs of wading boots over the last decade, I decided that I needed a pair of the old Weinbrenners. I got a good deal on a pair that's next-to-new. But they don't have the studs that enable the soles to last longer. The Weinbrenner studs don't resemble the screw-ins I see on other boots. Where may I find those studs similar to what you find on the Weinbrenners?