The set includes the pocket transmitter, the stationary receiver, and everything needed to use or install it. It comes with the MKE 1 electrostatic lavalier microphone – not just any lavalier microphone, but the best and most discreet for excellent presentations with the clearest sound. All sets also come with a rechargeable battery offering up to 15 hours of runtime. The battery can be charged via USB, with the cable provided in the box, and the USB port is likely just a few steps away from you. The two types of sets are the rack-mount version (-R), which comes with rack brackets and all necessary mounting hardware, and the case version (-C), which comes in a case without rack brackets, if you prefer not to permanently install the receiver. - The smallest lavalier microphone from Sennheiser in a set optimized for speeches and conferences. - MKE 1 | SL Bodypack DW | SL Rack Receiver DW | BA 30 Rechargeable Battery | Case or rack mounting kit GA 4 and pouch - Automatic frequency and interference management - Excellent speech intelligibility - Full and natural sound with low ambient noise - Lockable 3.5 mm mini-jack socket - Secure AES 256-bit encryption.