Sennheiser’s succesful wireless series are now at the third or fourth generation. although the top-end latest generation are a bit on the pricey side, the earlier generation are still available second hand at quite reasonable prices… if you know where to look, and know how to be patient.
I picked mine up from a professional musician who decided a cable served his purposes just as well, with less hassle.
the G2 series accept, instead of the bulky 9 volts block, two AA batteries. This is sooo much more convenient, since rechargable AA batteries are a lot cheaper than rechargable 9 volts batteries.
I’ve used it for practice sessions, partially because I wanted to show it off, partially to get used to cable-less playing, but mainly to see how long the non-chargable batteries would last.
We’re on nine hours and counting… Incredible!!