this is the third bluetooth earpiece that i've purchased for my motorola 815 cell phone. i am finally happy with this purchase. the other earpieces that i have purchased have not met my standards for a number of reasons including comfort, volume & static issues. this earpiece is extremely comfortable to wear all day. the volume is certainly adequate even while driving in a vehicle. the reasons that i gave this 4 stars are due to the 5 hour talk time, and the caller id only scrolls the number...not the name. maybe it does with the sony ericsson phones...not sure. all in all i highly reccomend this bt earpiece.