From the seller:

Wireless system offers easy set-up and high audio quality for virtually any application. Features include Automatic Frequency Selection, Automatic Transmitter Set-Up, Predictive Diversity technology, and removable antennas with rack hardware. Operating Range Under Typical Conditions 100m (300 ft.) Note: actual range depends on RF signal absorption, reflection, and interference Audio Frequency Response (+/– 2 dB) Minimum: 45 Hz Maximum: 15 kHz (Overall system frequency depends on microphone element.) Total Harmonic Distortion (ref. +/– 38 kHz deviation, 1 kHz tone) 0.5%, typical Dynamic Range >100 dB A-weighted Operating Temperature Range –18°C (0°F) to +50°C (+122°F) Note: battery characteristics may limit this range Transmitter Audio Polarity Positive pressure on microphone diaphragm (or positive voltage applied to tip of WA302 phone plug) produces positive voltage on pin 2 (with respect to pin 3 of low impedance output) and the tip of the high impedance 1/4-inch output. SLX1 Bodypack Transmitter Audio Input Level -10 dBV maximum at mic gain position +10 dBV maximum at 0 dB gain position +20 dBV maximum at -10 dB gain position Gain Adjustment Range 30dB Input Impedance 1 MΩ RF Transmitter Output 30 mW maximum (dependent on applicable country regulations) Dimensions 108 mm H x 64 mm W x 19 mm D (4.25 x 2.50 x 0.75 in.) Weight 81 grams (3 oz.) without batteries Housing Molded ABS case Power Requirements 2 “AA” size alkaline or rechargeable batteries Battery Life >8 hours (alkaline) SLX2 Handheld Transmitter Audio Input Level +2 dBV maximum at -10dB position -8 dBV maximum at 0dB position Gain Adjustment Range 10dB RF Transmitter Output 30 mW maximum (dependent on applicable country regulations) Dimensions (including SM58 cartridge) 254 mm x 51 mm dia. (10 x 2 in.) Weight 290 grams (10.2 oz.) without batteries Housing Molded PC/ABS handle and battery cup Power Requirements 2 “AA” size alkaline or rechargeable batteries Battery Life >8 hours (alkaline) SLX4 Receiver Dimensions 42 mm H x 197 mm W x 134 mm D (1.65 x 7.76 x 5.28 in.) Weight 816 g (1 lb. 13 oz.) Housing Galvanized steel Audio Output Level (ref. +/– 38 kHz deviation with 1 kHz tone) XLR connector (into 600 Ω load): –13 dBV 1/4 inch connector (into 3000 Ω load): –2 dBV Output Impedance XLR connector: 200 Ω 1/4 inch connector: 1kΩ XLR output Impedance balanced Pin 1: Ground Pin 2: Audio Pin 3: No signal Sensitivity –105 dBm for 12 dB SINAD, typical Image Rejection >70 dB, typical Power Requirements 12–18 Vdc at 150 mA, supplied by external power supply