The Shure BLX24R/SM58 Handheld Wireless System gives you world-class design and rock-solid build quality along with easy setup and operation. Thanks to Shure's cutting-edge QuickScan technology frequency-selection hassles are a thing of the past. The system includes the BLX4R rackmount receiver with rackmount kit and the BLX2/SM58 handheld transmitter with integrated SM58 cardioid dynamic microphone capsule.