Audio-Technica ATW-1102

Specifications
Overall System
Operating Frequencies     2.4 GHz ISM band (2400 to 2483.5 MHz)
Frequency Response     20 Hz to 20 kHz Depending on microphone type
Operating Range     30 m (100′) typical
Open range environment with no interfering signals
Total Harmonic Distortion     <0.05% typical
Operating Temperature Range     0° C to +40° C (32° F to 104° F)
Battery performance may be reduced at very low temperatures