All three have Shure's one-touch QuickScan frequency-scanning feature that quickly locates the best open frequency channel. For reliable operation this is super-important when working in busy environments with many radio services operating at the same time. RF interference is minimized or completely avoided.

Other good things to know are the 300-foot performance range and up to 14 hours of battery life. No worries about getting out range of the receivers and if you're not sure if and when you last changed the two AA batteries, there is a margin of safety. The transmitters come in body pack and handheld configurations with multiple handheld, lavaliere, instrument, and headset microphone choices.

There is the BLX1 Body pack Transmitter with Tini QG® mini XLR connector for Shure's lavaliere, headset, earset, and instrument microphones and guitar cables. The BLX2 Handheld Transmitter has an integrated microphone capsule option with your choice of Shure's PG58, SM58®, and Beta58A. This transmitter has a -10 dB gain attenuation mode for super loud singers and color-coded ID caps are available separately.

The BLX4 Single Channel Receiver has the aforementioned QuickScan frequency selection with up to 12 simultaneously running systems per frequency band. There are also XLR and ¼-inch output connectors. The BLX4R is the same system except it is half-rack size and has adjustable output level and removable antennas. Lastly, the BLX88 Dual Channel Receiver combines two receivers in one rack space unit and with the same feature set as the other two receivers.