Bluetooth is 4.2 (liberty+ has the newer bluetooth 5.0). i had no issues initially pairing and connections have been solid with (so far) no drop outs. later however, sometimes if only one earbud was paired, i had issues getting the other bud to pair and match its twin. in extreme cases, i’ve had to take them out, place them in the case and start over. it can be a pain, especially if the case is not nearby. i’ve had this issue with other brands, so it’s not unique to zolo. it happens rarely, but it is something to consider if you’re looking for wireless ear buds. once the tech matures, this issue should hopefully disappear.