The Mammut Wall HMS is a classic pear shaped biner, which is relatively lightweight and robust enough to take the rigours of most eventualities. It offers the full range of applications – from classic HMS securing, to use with modern belay or ascending devices.
Seems like a solid carabiner, but the screwgate opens way too easily. It fully opens and closes with a single flick. This might be handy for some people when making an anchor, but I wouldn't recommend as a belay biner in case it opens mid climb