I just ordered one. They hit you hard on shipping, the $9.95 price was around $16.50 with the cheapest shipping option. It looks nicely small compared to the Tekkeon MyPower lithium rechargeable I was planning to use (with the USB adapter they sent me). I wonder if the voltage is well-regulated enough for the MicroTrack, if you use alkelines or lithium AAs four makes 6V, NiMH gives 5V.
Jeff