Never any trouble with this unit at all - you supply your own earbuds/headphones.
Pack takes two AA batteries - I use rechargeables. Pack is made of plastic, so it's not as heavy as my guitar wireless pack. You can sync the pack to the receiver by either punching in the freq manually, or by using the infra-red scanner built in!
I have not played live for awhile, and I haven't gone with IEMs the last couple years so....this is just sitting in my studio mocking me