This is the Phoenix Jr IR strobe beacon
This 30x20x20mm (1.2x0.75x0.75") block of acrylic weighs only 8.5g (0.3oz) and has a 9v battery attachment point on the bottom, slightly covered by a lip. Inside the acrylic you can see the three IR LEDs and the simple controlling circuit board. Simplicity in design!
The 9V battery will provide 200 hours of strobing, according to CE Jay Engineering, and even after draining the battery of its primary charge, they suggest that giving it a2-3 hour rest can eek out a short while of extra strobing, in a pinch. The flash rate of 20 milliseconds every 1.3 seconds was specifically chosen to prevent confusion with small arms fire, which is a VERY good thing, to my thinking.
The clear case, and design allows for a 360 degree viewing angle, from around the beacon, and a 240 degree viewing angle from the vertical( due to the battery, obviously).
Whilst not "waterproof" the beacon is purported to function whilst immersed until the contacts fail due to electrolytic corrosion. That's pretty impressive. No switches, no moving parts, just the 9v connectors. Plug in a batter, and it's on. Pull battery off, and it is off.
I tested it with my Yukon 3x42 NVG, placing the beacon on my car and walking down the street until I lost line of sight, and I have no doubts that this beacon would be visible for hundreds of meters more. To get a decent photo, I took it inside, and with my iPhone, took a couple of "down the relief" shots.
Unlike some IR LEDs, those used in the Phoenix Jr are totally invisible to the human eye, with no tell-tale red pulse. This means for covert use, either in static positioning, or secreted on your person, and even through clothes, you can signal to NVG equipped observers.
I am throughly impressed with this piece, and am going to see a out placing an order for the non-export restricted waterproof carry case for it. I think this kind of item that would be ideal for assisting Search And Rescue teams finding me in the event that I have a misadventure. That or IFF when I am out laser tagging.