Shure MX890 Microflex Wireless Desktop Base For this wireless system component to work, please make sure your transmitter and receiver match in frequency range (style) Sleek, low profile design. Frequency agile, microprocessor controlled transmitter. IR link to SLX receiver for automatic frequency synchronization. Programmable frequency Group/Channel display. Programmable mute function. Operates on two AA batteries. Compatible with all Shure SLX Wireless systems. Supports Shure MX405, MX410, and MX415 Microflex Modular Gooseneck Microphones. CommShield technology for protection from RF interference.