Specifications:

System Performance:
Modulation: FM
Carrier frequency: 864 MHz (ch70 - UK) (LPD band)

T 105 UHF Transmitter:
Switchable choice of three transmission frequencies:
A = 862.945MHz
B = 863.455MHz
C = 863.770MHz
Power supply: 9 VDC, 200 mA
Weight: approx. 130g
Max. range: approx. 100 m

Full AKG price list 

AKG Wireless Headphone Transmitter

This trade-in unit is fully working and includes a compatible power supply.

Great if you already have a set of K105UHF headphones and want to be able to extend your music to different rooms or listen to different audio sources (eg hi-fi, TV, PC, etc) with one set of headphones. Just choose a separate transmission frequency for each source.

Otherwise, this unit could be used to transmit to in-ear-monitors (IEM) which can tune to the same frequency. These frequencies are within Channel 70, so are free to use in UK and do not require a licence.