I use a headlamp nearly every day in my work. 

In '06 I started out with a Petzl Tikka.  Great little headlamp, but doesn't have the brightness I need. 

In '07 I made the commitment to rechargeable 3.6v CR123 batteries after purchasing two Nitestar Luxeon 3 watt flashlights from ebay seller goldenpsx and being very happy with them.  I started looking for a brighter headlamp using CR123 batteries.  After researching several I chose the Princeton Tec Apex Pro (orange) and found one on eBay at a good price.

The Apex Pro is an excellent headlamp with one 3 watt Luxeon LED for spot and four small LEDs for flood.  Two brightness levels (hi and lo) for each.  90% of the time I use the flood LEDs.  10% of the time I use the spot LED when I need really bright focused light.  By the way, don't look directly into the spot LED.  It really is bright.

As good as it is, it does have one serious weakness.  After using it about four months, one day (Oct 07) I accidently put the batteries in backward.  It immediately quit working.  I heard popping and sizzling. Electronics fried.

I contacted Princeton Tec and they sent me a new one under warranty.  I told them they need to put a diode in the circuit to prevent the electrionics from being fried if batteries are put in backward ...which is easy to do.

Yesterday (10 Sept 08) I did it again.  Was in a hurry and accidently put the batteries in backward.  Popping and sizzling again.  Electronics fried.

I sent Princeton Tec an email asking for warranty replacement again since I feel this is a manufacturer's defect.  When they respond I'll update this guide and let you know what they decide to do.

The Apex Pro is a really nice headlamp, with this one serious flaw.  It would be easy to correct by putting a diode in the circuit to prevent reverse power flow when batteries are put in backward.  

There is nothing to prevent batteries from being put in backwards.  It's easy to get in a hurry and put them in backwards without realizing it.  Of course, by then it's too late.  As soon as you hit the switch, the the light is fried.

george (gpk9)

9/17/08:  Princeton Tec has not responded as yet to my 9/10/08 email request for warranty replacement.

10/24/08:  Princeton Tech has not responded.  I believe it is safe to say they won't respond. To me they are not standing behind their product.