Personal/ Lone Worker Device

Glen, you forgot to mention that you need 3G.

Mictrack forgot to mention that he has no idea what is a real Man Down Alert ;-) (which you need to provide a serious Lone Worker System).

Man Down Alert needs to detect over a time if someone was falling down by using intensive G-Sensor algorithm. It also must understand if someone was fallen down if device is NOT at a perfect 90deg angle on your belt!.

Wolf.

P.S. i know only Flextracks personal lommy 2 or so which can do that and is used in denmark by hospitals and governmental users for exact this purpose. but of cause its much more expensive than 25 USD Device...

Little late to this, but have you considered anything from Blackline Safety or Satellite?

There's a variety of models available, most of which include the items you have on your list. They also have models that operate outside of cellular coverage, which is great if you're working outside of 3G / 4G coverage but still want the security of knowing that people can find you if something were to happen.

They also include true man down protection, which as wwbusch aka Buwo points out is a crucial feature that most tend to overlook.

This site has a pretty extensive range / details if you're interested in more info: http://www.directsafetygroup.com/lone-worker-devices/