Featuring an integrated SM58® microphone cartridge, the BLX2/SM58 Handheld Wireless Microphone Transmitter delivers wireless audio with professional clarity and reliability. Works with BLX® Wireless Systems Offers up to 14 hours of continuous battery life with 2 AA batteries Allows for custom handle design at designstudio.shure.com Includes BLX2/SM58, microphone clip, 2 AA batteries, and user guide The BLX2/SM58 Handheld Wireless Microphone Transmitter works with BLX Wireless Systems. Features; Integrated microphone capsule design Lightweight, rugged construction -10 dB gain attenuation Color ID caps (available separately) Warranty: 2 years.