Could this be a much cheaper alternative to the Greatland LASER flare for emergency signalling?

http://www.dealextreme.com/details.dx/sku.12337

http://www.equipped.org/rescuelaser.htm

I would never trust anything from GearExtreme with my life. I've seen several things they've sold, and lets just say they were underwhelming.

Not for USAmericans

Its hard to compare lasers without specs,
but a few in the same price range as greenland,
the range of 30mW green lasers is 10 miles,
50mW 25 miles, 80mW is 35 miles.
The greenland Green Rescue Laser Flare is 30miles.
Lasers in the price range of the one you linked to say the range "in excess of 6000 feet." which means 6001feet
So besides being apparently illegal for USAmericans to buy, they don't sound that great, but might be better than an actual flare

DealExtreme is a Chinese retailer of Chinese-made cheap gadgets. While I personally believe DX tries to operate on the same level as Western retailers when they can - in terms of truth-in-advertising etc - their Chinese suppliers are *not* particuarly honest or safety conscious.

You need to understand that the specs on DX's web pages are manufacturer claims. There's no telling how much 532nm green that "30mW" laser produces, and much more important, there's no telling how much 1064nm infrared it emits, and it's the 1064nm that's dangerous. A badly made 30mW greenie can easily put out enough 1064nm to blind you and since you can't see it you won't know until afterwards.

A red laser won't put out any infrared. Blue will. Ultraviolet lasers (parts salvaged from consumer BluRay players) won't but they have their own hazards.

Bottom line: for red it's not dangerous to give DX a try, but for green stick to someone reputable like
Atlas Nova . That link goes to a model with several beam patterns other than a point, also important for a rescue laser, and it won't leave your rescuer blind (SAR people appreciate that).

For anyone who doesn't know why the U.S. is a bit down on these green lasers, here is why http://www.photonics.com/Content/ReadArticle.aspx?ArticleID=30198

"Pilots have reported more than 900 laser incidents nationally since the Federal Aviation Administration began recording them in late 2004." (And that was dated 7-2007.)

A local schmuck kept his green laser fixed on a police helicopter so long that they were able to alert a ground patrol, who arrested the idiot.

Sue

Plan B: Take it as a given that some SOB is going to fire a beam riding missile at you and stick a H.A.R.M with a frag warhead down his or her throat.

That should discourage such behaviour quite nicely.

I'd love to know the difference in distance visibility between a upper-end LED light (like a Fenix or Surefire single CR123 version) in flashing mode and a Greatland Rescue Laser Flare.

I have both and would like to test it, but unfortunately I don't live near mountains nor do I own a helicopter (darn!). The single CR123 LED lights are VERY bright and much smaller & lighter ... and of course more multi-purpose.

Don't be so quick to judge; half of my Recyko stock is from Deal Extreme.

To some degree these are exaggerated concerns: battery-power hand-held greenies simply can't put enough energy into a cockpit to damage the eyes except at takeoff or landing & if you get lucky. The beam dispersion is too great. Loss of night vision is the only potential issue.

(my lasers have all come with beam quality measurements and it's straightforward to calculate the diameter of the laser spot at a distance and the power loss)

(not to mention the sheer difficulty of hitting a target with a narrow invisible beam - I assume a rescue laser is useless unless it has an output pattern other than a point since you can't hit a rescuer in the sky with a narrow beam)

The real risk is medical helicopters as they need to get close enough to the ground to be at risk. Other aircraft shouldn't be in that position (due to hazards to everyone on the ground when they crash into a power line etc).

Goggles that block 532nm green work very well and are inexpensive. I believe the Air Force has incorporated 532nm blocking for a while.

Infrared lasers are another story. They are extremely dangerous because the beam cannot be seen and does not trigger the blink reflex. Every DPSS laser (green, blue, yellow) has an infrared laser to power it and if it's made poorly can easily blind people. This is the reason for the FDA regs cited on the Deal Extreme site, not aircraft.

The electronics I've seen from them are all on sketchy side of bad, particularly in terms of "does it look like it will keep the water out". The few stitched items all had horrible stitching. And for the tiny number of tritium capsules that made it to the states (not their fault, in all honesty) were very dim, like they'd been sitting in a warehouse for a few half lives or there was very little tritium and a lot of something else (which I would call their fault). Those all point to a systemic QC issue, that's why I say I wouldn't trust them. If you've had better luck, all the more power to you.