Grivel
Plume Nut

Grivel's line of carabiners are some of the lightest, most compact and interesting designs. They tend to be focused on use in alpine environments which favors low weight, ease of use with gloved hands, and features which function when packed with ice and snow. In the Plume Nut, Grivel has created an ultralight, ultracompact full-strength locking carabiner - the smallest and lightest on the market as of 2023.

The low-profile sleeve might be a challenge to operate with gloves, but the Plume Nut would make a great emergency locker, or used in an application where it left locked for a while. It could easily replace non-locking carabiners trading security for size without increasing weight.

The gate is turned (machined) down leaving the nose end a larger diameter than the rest, which acts as the sleeve stop and provides more material for the keylock latch. I suspect the thin locking sleeve would not resist much force against the gate face, although the risk is minimized due to the short gate and compact overall size.

There is no relief hole for clearing snow or debris in the rear of the keylock pocket, but a generous pocket size and rear chamfer should help encourage foriegn material to exit without too much trouble.

I have listed the gate opening as 17.56mm, but this measurement is from the corner of the fully opened gate and the basket, as this would be the limiting factor when clipping large diameter objects. When fully opened, the space between gate locking sleeve and nose measures 19.08mm.

And since I don't have it listed anywhere else, part number is sometimes prefixed with an "RS" (RSK3N) for Rock Safety Carabiner K3N (PLUME screwlock).