About as bombproof as it gets.
Battery drains fairly quickly in turbo mode.
For pursuits like alpine climbing, high-altitude mountaineering as well as Backcountry rescues, you’ll require an appropriate headlamp that can stand up to a lot of abuse. Fenix’s model HM50R is suited well. The headlamp is durable, and has a complete aluminum casing and is powerful, with a max output of 500-lumens and beam length of about 250 feet. It also has waterproof and dust-proof that has an IP68 rating that means it’s capable of being submerged the water to 2 metres for up to 30 minutes. In addition, the design is also well-designed with an auxiliary switch on the side that allows you to switch between different the different settings (the headlamp comes with four levels of output) as well as a reflective headband and the ability to work with cold-resistant CR123A batteries.
There aren’t many who require the high-end features or the ultra-tough construction however the good thing is that Fenix is affordable for the output and performance that you can expect to get. It is possible to upgrade to a higher-end model, such as the HL60R above but it’ll cost an additional $14, and include a bigger design. Remember that for all headlamps with high power it is best to select the most bright setting when you need to. For example, the Fenix’s 500 lumen “turbo” mode can drain the battery in less than 2.5 hours, while lower settings span from 10 hours to 4 days (and more with mentioned C123A batteries).