Mammut  Classic HMS Screwgate Carabiner

I have one of these each in blue and pink for each of my belay devices. I got them mostly because the colors were fun and I really like the orange unlock indicator. They're a great size, easy to use, and don't unscrew themselves. My only gripe is that they frequently spin around and end up either backwards, or, even worse, crossloaded sometimes when I have slack in the belay. I'm not sure how much of that is operator error, belay device design, or carabiner design, but I haven't had this experience with other carabiners.

Great locker. It does what you want a locking carabiner to do, is super light, and easy to hold and clip onto bolts. The only problem is that it suffers from the same problem all screwgates do: risk of overtightening, especially after being weighted and pressed against the bolt. This is all screwgate lockers though. Just don't screw it in 100% and you won't have a problem. The orange stripe to see you're not screwed in is a nice touch.

I’ve used several screwgate locking carabiners over the years, and the Mammut Classic HMS Screwgate (blue) has quickly become one of my absolute favorites—especially for canyoneering. What stands out right away is how lightweight it feels for the size without sacrificing strength. It hits that perfect balance where you don’t feel weighed down on long approaches, but you still have complete confidence in its durability when it matters most. The build quality is excellent—everything about it feels solid, smooth, and well-finished, exactly what you’d expect from Mammut. The size is just right for versatile use. It’s large enough to handle everything from rigging to PAS's to anything you'd need it for in a canyon, yet not so oversized that it becomes cumbersome on your harness. The large gate opening is a huge plus—it makes clipping ropes, webbing, PAS's or anchors quick and hassle-free, even when you’re wearing gloves or working in awkward positions. One feature I really appreciate is the orange warning paint on the screwgate. It’s a simple but effective visual cue that immediately tells you if the gate isn’t fully locked. Overall, this carabiner inspires confidence every time I use it, which is exactly what you'd want in any gear that is keeping you from falling hundreds of feet. Lightweight, strong, thoughtfully designed, and easy to use—it checks all the boxes. Easily one of my go-to screwgate carabiners.

Great alternative to the Petzl Atache! Super versatile size & great for master points, or anywhere you want an HMS carabiner. Notchless gate & warning marker makes it very easy to use & is a good visual reminder that the gate is locked. Weight and strength are both excellent & this is just a really nice carabiner. Highly recommended for belaying, using as a master point, or anywhere an HMS is needed. I usually have two on my harness at all times üëå

Love the bright color. It’s great for distinguishing between gear. I use the normal HMS for anchors and pink for belay devices. The color indicator for locking is also a really nice touch. They are a great size. I bought some two years ago and the color has barely warm off. I just bought two more. I also have used them on river trips. Great for flip kits and just attaching things to frames. The bright colors add flavor to a normally mundane piece of gear

Good standard locking carabiner. Used when building anchors. I've been using them all summer in Kalymnos and they've been great. Also used with a gri gri but the shape is not the best for that as it gets stuck on the smaller end sometimes. Good for rappelling, building anchors and multi pitches as well. Fun Colour is a bonus! Durable and quality gear, I would buy this again. This is your good old locking carabiner.

Great carabiner with nice features. Use it mostly for building anchors. Love the orange "gate unlocked" indicator, and it's a nice size for doing everything you need a basic screwgate to do. Don't love the hand feel as much as I do with some other 'biners, but I think this is super personal.

Very easy to use. I do like the color options (of blue, pink and purple) as well. The orange area that shows that the screwgate is unlocked is very helpful visually to remembering to lock. The screwgate itself I have found does not lock up or get too tight, as well has a good grip.

I would say this is almost comparable to the Crag HMS carabiner, but it's just a hair smaller so it's a tiny bit more awkward for munter/ clove hitches. Still just as robust & the locked mark is a nice feature.

Solid carabiner for climbing at the gym and belaying. I like the orange indicator showing me if it is locked or unlocked. I use it weekly at the gym and it has held up well after all this time.