I bought some other 'crampons' last year, that worked, but fell apart when I walked over the icy gravel that we have out here in the country.  These are designed so well that our gravel drive and street did not affect them at all.  And, they were less expensive!
Do not get any kind of crampon that looks like it has springs that bite the ice- they break all too soon.  This design was great, and I'm quite impressed!