Whilst at Hidden Earth 2015, I was looking for a new caving lamp. There was a choice of five different lamp manufactures showing their lamps, so I spent time vesting and talking to them all. But the Earthworm took my interest, I returned to their stand many times throughout the day to have a play and ask lots of questions which were all answered well. And in the end I made a purchase of their Earthworm2 lamp, the only weakness that I could see was that the battery is not in a metal case (but one will become available in the new year). But as it happened, I found that the battery fits nicely inside my old Pertex Caving Helmet as there is lots of room between inner webbing and outer shell, even with the battery in place there is still approx 10mm clearance between my head and battery.

Today was my first venture underground to see how it performs. We popped up Northwest Inlet in Craig a Ffynnon and I found that normal caving was well let using the second light setting (five settings in total). Once we got to some of the larger sections of cave passage, I could try the other settings and these all performed well lighting up the whole passage nicely, as even the highest light setting still has a wide beam and not a narrow spot. This makes cave photography a lot easier, as the auto focus on camera could see what to focus on. Another nice feature is that when the light is set to its highest brightness 1800 lumens, it will return to a lower brightness after two minutes.

But for me I'm well impressed especially at it's retail price of ?225.

Not sure about mounting the battery inside the helmet.  I thought that if something or somebody heavy dropped on your head, the helmet shell would flex on the webbing to absorb the blow, and the space 'twixt shell and webbing was there to allow for this.  Mounting the battery box there could result in most of the force of the blow being efficiently transferred to a small area of your cranium...

Others, however, might see fit to disagree...?

With you on that one Roger, the clearance between the cradle and the shell is there for a reason - to absorb shock.

Helmet impacts while climbing, yes; roof collapses in a cave?... the least of your worries will be whether you have a battery mounted inside your helmet cradle. It probably won't make the slightest bit of difference.

Roger didn't mention roof collapses specifically, just heavy people or objects. And quite often it's you who falls, not the object. I know from having done so many years ago, but fortunately I landed flat on the deck, not head first. Anyway, this is a lamp review.......

But I did say that there is still plenty of clearance, as the battery is quite slim. Unlike my climbing helmet where there is minimal clearance between cradle and shell.

Yes I noticed you said that. Some helmets fit quite snugly though. And are the connections good? The corrosive and smelly interior of my helmet might quickly destroy any good connections!

Thanks for your review, ogofmole; I looked at these lamps at HE and was tempted . . . .

Well when the new battery outer case comes available, I will obviously be getting one. As at the moment I felt that the battery was the only weakness with the set up. But overall I'm still very impressed with the performance of this lamp.