I need a new strap for one of my SMC crampons and since the company stopped making them quite a while ago, even good used straps are hard to find, so if you ever try crampons make sure the straps are all there. The metal portion is made out of chrome moly heat treated to almost wood pecker lip hardness, so a hunter will never wear them out in one lifetime. My primary pair was originally a rental and has probably gone through two lifetimes of use and wear is still minimal - it’s actually nice the sharp corners have been worn down a little and are less likely to damage a pack - for hunting there’s no advantage to sharp points.
The sizing of discontinued things can be confusing, but size 12 hiking boots fit really well in SMC’s medium. There is quite a bit of adjustment in length so I’m sure they would fit size 10 to 13. If they are for more bulky winter boots I’d go with a large size to have enough width and the length can be adjusted down.
There are still some great deals to be had on eBay - yesterday I checked out of curiosity and at least 3 pairs were under $30. One pair had brand new straps so I picked them up. This should hold up to at least a few generations of use after I’m gone.