The is one of the following closely-related notched belay tubes:

Image Device Sides AL-NASR Open LACD Evo Alpine, Version A Closed LACD Evo Alpine, Version B Open Rocteryx Open

Each of these is larger and heavier than the averages for the belay tubes in my collection. The extra mass helps from a thermal perspective, but I find thse to be simply too large for my taste. The LACD Evo Alpine, Version A does not have the lightening cutouts, and so it is the heaviest of the lot. I would rather carry a lighter belay device. Less metal means less weight to carry, but it also means less ability to absorb heat. For belaying, this is not usually a major concern, while for rappelling, any belay tube can get quite hot.

The top surface is stepped, allowing for deeper rope grooves without lowering the notches. The V-notches used in this design do not seem to be very effective at increasing the braking force. The notches do not have the narrow angle found on the Trango Jaws and its equivalents, so they do not create the same wedging action.

Normally I rig for belaying from the harness while using the notches. Reversing this arrangement removes the notches from play, resulting in less friction for braking.