A tad smaller than most HMS/Munter biners, but still big enough to be used for belaying, or as a central point in a belay.
Quite light, Keylock and not extraordinarily expensive.

Also i like the fact they they did hotforge it, but left the "belay area" round stock. Much smoother to use.

The inner helmet is more or less a standard styrofoam helmet, with all the pros and cons that go with it. However the top seems to be rather thick, so that make might make it better for top impacts, but it also adds a bit of bulk, which - at least for me - is no problem.
It fits me quite good, however it interferes a bit with my glasses, or to be more correct with the "arms" (sp?) of it, since they are straight (Oakley "sports glasses").
The second, alpine, shield is a good idea - at least in theory, and i hope i never have to test it in practice.
However there are three issues:
The headlamp clips become more recessed. Not an issue if you put the headlamp on before you need it, but trying to get it on in the dark, while wearing gloves might be a challenge.
Most vents get blocked. Not an issue or actually a benefit for colder stuff (ice/alpine), but for summer alpine, or trad multipitch your head will get warmer.
At least on mine, the inserst for the screws are a bit misplaced! The alpine shield is thus hard to screw on, and ends up sitting weird on the helmet. On one side i have lots of room between the shield and the helmet, whereas on the other side it touches the helmet, and two of the screws are quite tensioned. Looks stupid, and i will probably wreck the inserts faster than i want to :(
If you want to get this helmet, make sure that the inserts are placed right!

The Oz is similar in size to the BD neutrino, and bigger than the camp nano.
Does what its supposed to do, but is nothing special. sure, its very light, but the specs (while surely safe and ok) are nothing special. The neutrino is a tad stronger (and not too much heavier) and somehow "feels" better (nicer to clip, more confidence inspiring).

To me it looks like BD at first didnt react to the whole trend for ultralight biners, because they had long ruled that field with there supreme neutrino, and when they realized that there where biners that where actually superior to it they had to act too quickly, building a biner that is just a tad smaller and thinner than the rest, but nothing special like for example the DMM pieces.

qwert

Nice biner, and the fact that it has a keylock nose is very welcome.
Not ultralight, but also not heavy.
The price is also ok.

But on mine the locking sleeve got quite loose after a few years. Not so much that im concerned about it, but enough to make it a little bit annoying. This is something i have so far only seen on my positrons, whereas other biners (Kong, Camp, Wildcountry, ...) dont show such a behaviour.

qwert

not cheap but you get what you pay for.
with its structured surface its surprisingly comfortable for its weight, and its insulation capabilitys are prety good too. just dont use it as the only mat when you try to sleep on snow.
also the egg crate structure will catch snow ice and dirt, but i havent found this to be a problem so far.

qwert