Shure QLXD4 Digital Wireless Receiver Frequency H50FEATURES Half rack QLXD4 Digital Wireless Receiver quickly finds open frequencies and deploys them to transmitters via the one touch sync function. Works with QLX D Digital Wireless Systems With transparent 24 bit digital audio quality and incredibly efficient RF spectrum usage, the QLXD4 Digital Wireless Receiver combines professional features with streamlined setup and operation. Automatic scanning quickly finds open frequencies, and one touch IR