Grivel Rambo 4 is simply clever. It's basically a monopoint, but with a small stabilizing second front point. Rambo 4 is a bit heavy and as difficult to adjust as any rigid crampon, but climbing with it is just pure joy. It's penetration abilities combined with it's stability is simply unmatched. I also like the way the active antibots work, they literally blow off the snow every time you step on the crampon.

There are couple of issues though with Rambo 4. First, it is rather heavy, second the adjustment requires tools, though the structure is built around "one bolt adjustment" principle. Also while fenerally speaking Rambo is very durable and reliable piece of equipment, there are two weaknesses; the metal thing attached to front bail that's used to route the crampon leash and the antibots. As with many other similar Grivel designs the metal thing that's attached to front bail tends "break off" from the bail (mine is fine, but one of my friend's isn't + I've seen several other Grivel crampons suffering the same problem). I've also noticed that the yellow central "active" piece of the antibots tend to come off from the small plastic "nubs" that keep it on its place. The antibot problem is easy to fix, it's not a permanent damage, but still annoying.

Overall I've been very happy with Rambo 4s. Though at this point for technical ice I would probably purchase Grivel G20s.

This crampon feels very stable and is easy on the calves. I found it easy to adjust and fit was great with my boots. Other than the weight they are by far the best I've had a chance to use. The real draw back is the antibott plate that is not durable.

Agreeing with the review below, climbing with these goes smoothly! But adjusting them to a smaller shoe (size 5½) took a lot of work, and the crampoon being adjusted to the smallest possible size, the anatomic curve is almost too curved compared to the shoe. So absolutely the crampoon of choice if your shoe size is above 6:)