Hi, I'm a US dealer for Archon (full disclosure). I'm not familiar with the DH30; it looks like a variation or earlier version of the DH36 - see the current product list at
ARCHON. I have some DH36 units that will be selling via Amazon shortly; or if anyone contacts me here, I can ship directly to them. If anyone wants to review a unit, contact me, and I'd be happy to offer a discounted price in exchange for them posting their honest thoughts on the product.
I first saw some fellow cave divers using a DH36 in Mexico and I was impressed with the build quality and design for the money. Instead of using bundles of 18650's in parallel/series, they use 3 26650 cells in series, which are larger diameter and capacity (4000 mAh). Unlike most can lights, instead of charging the pack directly, you remove the 3 cells individually to charge. A disadvantage of this is that you need to charge 3 batteries separately, an advantage is that you can buy replacement 26650 cells for less than $10 apiece - so a replacement or spare set for your can light would be $30. The light is rated at 240 minutes on high, so despite a comparitively small battery pack, the burn time is very nice.
The light head and canister is aluminum with what seems to be a durable finish, looks like powder coating. The lens is 8mm thick polycarbonate, (about 1/3" thick), and the whole unit is rated for 330 ft (100m). The light head is on the large side compared with most single emitter light heads, but smaller than an HID reflector. There is a magnetic switch on the top of the light head - in the pictures it looks like it could be thin stamped steel, but in person it looks like a solid piece of machined stainless.
They use very nice strain reliefs, and the cable has a tech-flex type braided coating. While this could be more durable, it also does make it stiffer than I'd like. The stock cable is a bit longer than a typical can light as well.
There are 3 LEDs which each have a dedicated reflector; the reflectors are small compared with a more typical single element LED can light. However, they still manage to achieve a nice hot spot (rated at 8 degrees - seems about right to me) with an ample amount of spill. It's probably not as efficient as a larger reflector, but since it is a very bright light, it would be quite effective for both signaling and illuminating.
Overall for the money it is a very impressive light. It's not a perfect design, I've been discussing some changes with Archon, as well as some other ideas. If anyone has any questions or feedback, please contact me.
The W40VR video light is another light I'll be carrying - that one I am very excited about - it is a very potent and reasonably priced little unit. They also have some very nice GoPro trays/mounts that hold one or more video lights and a go pro in very compact form factors.
Rob