Pairing this device to both a Treo 750 and AT&T; 8525 was easy enough. However, even though the manual says that that the device will pair with up to 5 phones, switching between them didn't quite work. For example, after BlueAnt successfully works with the Treo, I would turn off both the BlueAnt and Treo's bluetooth. After that I would enable 8525's bluetooth and then turn on BlueAnt. The 8525 takes a long time before it'll connect with BlueAnt (keep in mind I already went thru the pairing setup process for both phones). The same can be said about the Treo if I do the reverse (make sure 8525 works first, and then try to connect with Treo). BlueAnt's connection is almost instantenously if you only connect with the same phone as the previous connection.This is not a big issue since the wife and I don't switch cars that often. However the straw that broke the camel's back is that the microphone shaft refused to remain in the off (retracted) position after 1 day worth of use. It seemed that there is at least 1 more report of this from previous Amazon reviews (about 2 weeks ago). The microphone shaft is the reason I bought this product. I hate having to press a button for 3 to 4 seconds in order to turn other bluetooth device on/off. It's ironic the feature that sold me the product is the main reason I am returning this and getting a refund.