The Fitness Audio U-Series 16 channel UHF Transmitter is your best bet for sweat! The electronics inside are protected with a coating of corrosion-resistant lacquer for extra sweat protection. If your Aerobics, Group Fitness Room has a busy schedule with a block of 4 hour-long classes every evening, then investing in a spare Aeromic/Cyclemic and Body Pack Transmitter is a must! Alternate them so that they 'dry out' between uses.
16 switchable channels with more than 8 channels compatible for multiple room or dual channel systems. Replacement belt pack transmitters are available in 630-650Mhz, 598-610MHz and the 520MHz group.