Awesome device...great sound clarity and comfort. I got mine brand new and sealed for only $30 off of EBAY!!!
Believe me even though its a great device it's not worth more than $30-$40!
Anyway...I have it linked to my T-mobile 7290 handset and it works great...only downside is that it sort of drains battery life quicker on the 7290 when talking on it.
I also look like a STar-Trek geek with the Hs820 in my ear...so I usually carry it in my pocket or clip it to my sunvisor when in the car....