I put a pair of Viper Crampons, the latest and greatest from Tubbs, on an old pair of Tubbs Altitude 25. What an improvement!!!
Well worth the $60 I paid through REI. You can get'm direct through K2 in Seattle for $20 + this and that. The crampons were on my snowshoes before K2 responded to my e-mail.
While you are at get the Active Fit bindings, too. I think the crampon/binding package is $85.
