The AKG WMS40MINI2-MIX-SET-US25BD Wireless Handheld Microphone System with SR40 Mini Receiver, HT40 Mini Handheld Transmitter, and PT40 Mini Pocket Transmitter and Accessories (537.900MHz - 540.400MHz) uses a single 1.5-V AA size battery.

Small Size Big Sound
The WMS40 mini2 Sets ensure brilliant sound and ease of use at an unbeatable price/performance ratio. Unique HDAP (High Definition Audio Performance) technology ensures the best possible, most realistic sound at any time. The SR40 mini2 receiver provides three status LEDs each for channels 1 and 2, indicating ON/OFF status, received signal strength (RF OK), and audio clipping (AF CLIP). The VOLUME control sets the level at the ¼" output jack. Each receiver comes with a universal 12-V switched mode power supply with EU, UK, and US adapters. The illuminated ON/OFF button switches both channels on and off simultaneously. The PT40 mini bodypack is probably the smallest and lightest transmitter in its class. A reliable mini XLR input allows you to connect every compatible AKG miniature microphone. The rugged HT40 mini handheld transmitter features an ON/OFF/MUTE switch and a sturdy wire-mesh cap protecting the cardioid dynamic microphone element. Battery life is the same legendary 30 hours off a single AA battery as for the standard WMS40 models, reducing the need to replace batteries and thus saving real money in the long run.

Specifications:

• Carrier frequency range 660 to 865 MHz
• Modulation FM
• Audio bandwidth 40 to 20,000 Hz
• Frequency stability (-10°C to +50°C) ±15 kHz
• T.H.D. at 1 kHz typ. 0.8%
• Compander integrated
• Signal/noise ratio typ. 105 dB(A)
• RF output typ. Max. 10 mW
• Power requirement single 1.5-V AA size battery
• Battery life >30 hours

Included:

• 1 x SR40 Dual Mini Receiver
• 1 x PT40 Mini body-pack transmitter
• 1 x HT40 Mini handheld transmitter
• 1 x MKG L Instrument cables
• 1 x Universal power supply with US

This microphone system is compander integrated.