Our Fitness Audio 16 channel UHF Transmitter. We protect the electronics inside with a coating of corrosion-resistant lacquer. If your Group Fitness Room has a block of 4 hour-long classes every evening then a spare Aeromic/Cyclemic and Body Pack Transmitter is a must! Alternate them so that they 'dry out' between uses.
There are 16 switchable channels in the pack. At least 8 of them are compatible to work in multiple rooms or in dual channel systems (excluding 520-526MHz which only has 6). It's powered by a 9V battery. Use EverReady Alkaline or re-chargeable NiMH batteries for the best results.