MIPRO Miniature Headworn Transmitter. Use in conjunction with MU23d headworn microphone for complete freedom - no bodypack or cable. Features a built-in rechargeable lithium battery with a quick charger. Use with MU23d headworn mic (purchased separately) and transmit to ACT311B, ACT312B or MA Series Portable PA's fitted with compatible modules. 5NB frequency band.