Soon after field testing the Mammut Smart 2.0, I became acutely aware that the carabiner I had paired with the device — the Metolius Element II — was sub-optimal:
- The I-shaped stock in the basket end meant that there was less surface area in contact with the rope, and brake effectiveness was reduced.
- Lack of anti-crossloading features meant that the carabiner sometimes flipped/rotated during usage.
The two features I needed for it to pair nicely with the Smart:
- Round stock at the HMS end
- Anti-crossloading
A third nice-to-have feature was an auto-locking gate.
After some suggestions, I landed on the DMM Ceros Locksafe, which ticked all three boxes. The Ceros is the younger brother to the DMM Rhino — Rhinoceros, get it? Ha ha.
The carabiner weighs in at 94.42g. Certainly not the lightest, but for me, weight is not a consideration when belaying in single-pitch sport climbing situations. This particular variant — the LockSafe — has a triple-action gate, which likely adds some weight. DMM also sells screw gate and double-action twist-lock gates with the Ceros.
For comparison, a comparable Edelrid HMS Strike Triple-locker weighs in at 66.86g. My Grigri weighs in at 176.14g.
DMM has opted to construct the majority of the carabiner in an I-beam style for weight savings, but has continued to provide a full round stock at the top bar (aka basket). This is preferable for tube-syle devices, and works well with the Smart. No complaints here.
The gate action is surprisingly nice. When opened, a spring provides some nominal resistance, but when fully opened, there comes a point at which there seems to be less resistance, meaning you need less force to keep the gate open. It's the small things that make this an outstanding belay carabiner.
The "horn" on the Ceros (and Rhino) will not work to keep a Mammut Smart oriented correctly — it was designed for the Grigri. However, the captive gate functions extremely well at keeping the device from crossloading, or the carabiner from flipping.
Unlike some other belay carabiners, the anti-crossloading captive gate opens downwards towards the narrow end. It allows for the carabiner to be secured onto the belay loop with a single upwards tug. Super quick, super secure.
In short — would buy again, would recommend to others.