Danny R.wrote a review of Grivel G12 Crampon on June 27, 2019
Familiarity: I've put it through the wringer
I've used many different brands of crampon and settled on the G12 "Cramp-o-Matic" as my all-around pair o' spikes. These crampons performed well on WI4+ sport laps in Colorado as well as load-carrying up steep frozen snow slopes in the Andes. These crampons are quite stiff and performed well on all footwear I put them on. While some folks prefer to have vertical front points, I find the horizontal spikes can be just as secure (with good footwork) on vertical ice and still perform just as well on less technical terrain. That being said, I would not recommend these crampons for mixed climbing or very overhanging ice lines.
The fit: These crampons were among the easiest to adjust that I have used. The toe bails fit snuggly to both my climbing boots and touring boots. The heels are very secure and I did not feel any wiggle even when navigating short rock sections in them. The adjustment system took a few tries to get right but now I can change the length quickly and easily from my touring boots (Scarpa Maestrale 27.5) to my climbing boots (La Sport Nepal's 44). I'm a huge fan of the front leash loop. No more fiddling around to run your ankle leash under your toe bail in less than ideal conditions (Warning, this metal part is quite sharp and put a hole in a pair of liner gloves but I guess that's part of the joy of alpine climbing).
Also, the bright yellow is a nice feature for trying to find your gear during alpine starts.