Fitness Audio 16 channel UHF Transmitter.
The electronics inside are protected with a coating of corrosion-resistent lacquer for extra sweat protection.
If your Aerobics Room has a busy schedule with a block of 4 hour long classes on every evening then you can invest in a second Aeromic and Body Pack and alternate them so that they can "dry out" between uses.
16 switchable channels with more than 8 compatible for multi room or channel systems.
Tx in 630-650Mhz.