tinyloc trackers

[Hermit]

i have just been looking around and found these trackers

http://www.tinyloc.com/us/

and would be interested in what you know or think about them

just to add to this on the UK tinylocs site it also says that tests have shown that useing a 5 element yagi aerial can increase range by 30% ,i have added this as its not on the US site