Anyone who climbs knows the Petzl brand, but even a lot of climbers don't know the whole breadth and depth of Petzl's product lines. Divided into sport and professional categories, there is a lot of overlap in the types of products - helmets, ropes, harnesses, lights, etc. - but the actual products themselves are carefully built to different standards for different applications.
The Pixa 1 HAZLOC headlamp is a great example. A sport climber would look at it and say, "too dim, too bulky" and move on. But hold on there hoss, this is a horse of a different color. Compared to, say, the Petzl Tikka sport headlamp, also a single LED design, the Pixa is indeed heavier at 7.4 ounces (with 2 AA batteries, included) versus 4.2oz for the Tikka (3xAAA). And the Pixa is about twice as big, with a dimmer LED: 20 and 60 lumen low and high modes versus 20 and 100 for the Tikka. That's a big difference in range, but even more of a difference in run time: 26 hours on high and 3.5 on low versus 180 and 120 hours for the Tikka.
But the Pixa is built this way for a number of very good reasons, perhaps the most important of which is that it won't blow you into a million pieces in the presence of certain gases. And we're not talking about the noxious but ultimately nonexplosive fumes emitted by your climbing partner, bad as those may be. The Pixa 1 Pro is available in two versions, ATEX (European) and HAZLOC (North American). Check out the links for specifics - and FYI if you need specifics you should be contacting a professional - but we're talking about a selection of gases, vapors, liquids and dust that might be found in certain situations. In those situations you need a lower power lamp to reduce the risk of an arc or other event that might set off a perfect storm of fuel and oxygen.
Given the extreme environments that the Pixa is likely to be operating in, it has a few other features of interest to those who want to keep all their orifices, organs and limbs in their original condition. The Pixa is impact, crush and chemical resistant, and waterproof to one meter (IP 67). It has controls that are easily operated with gloves on, and the light output remains constant until batteries are low when the Pixa switches to reserve mode with a remaining burn time of ten hours. The light housing itself rotates so the lens faces the hard plastic backing on the band, and the rotation will automatically turn the light off to prevent accidental discharge while being stored and transported.
The Pixa 1 comes with a helmet adapter that works with any standard 20x3mm slot, such as Petzl's own ALVEO and VERTEX models. It's also available as a Pixa 2, Pixa 3 and Pixa 3 rechargeable that are progressively more powerful. Overall the Pixa headlamps are great products for specific environments, intended for professionals who understand their limitations and usage. On the lighter side, they also are remarkably resistant to five year olds who like to swing them by the band against hard surfaces. In this application the Pixa 1 in particular, with its lower output, has one final feature to recommend it: the LED is eye safe, formally classified as risk level zero compliant with the IEC 62471 standard.