Move freely! With the WMS 40 PRO sports sets. The comfortable C 555 L head-worn microphone and the ultra-light PT 40 PRO bodypack transmitter afford the greatest possible mobility. Optimum intelligibility and proven AKG sound quality. The Sports Set Flexx features selectable frequencies. The diversity receiver ensures the best possible reception at any time, an ideal feature for the gym where users tend to move about quickly. The C 555 L uses special moisture and pop shields to keep any moisture out of the microphone. The transmitter operates for 30 hours off a single AA size battery, saving frequent battery replacements and thus a lot of money. 1) WMS 40 PRO SPORTS SET FLEXX ; 1 SR 40 FLEXX ; 1 PT 40 FLEXX ; 1 C 555 L ; 2) WMS 40 PRO SPORTS SET SINGLE ; 1 SR 40 SINGLE ; 1 PT 40 PRO ; 1 C 555 L ; System components are also available separately. Optional microphones for PT 40 FLEXX and PRO. Consumer Alert (for US users) – Most users do not need a license to operate this wireless microphone system. Nevertheless, operating this microphone system without a license is subject to certain restrictions – The system may not cause harmful interference; it must operate at a low power level (not in excess of 50 milliwatts); and it has no protection from interference received from any other device.