The Deoxit D5 is our "magic spray" that cures the crackles from Aeromic connectors and Transmitter packs.
It's only a small 20ml size but just put one little squirt into the connector, hold the connector upright and count to 10, then smack it into a tissue held in your other hand and look at the black stuff it flushes out! Yuk! That's dried-up instructor sweat for you causing those crackles by interupting the signal flow. Now do the same for the Bodypack Tx and also spray a little onto a tissue and polish up the battery tags if you can see them - they can get tarnished by sweaty fingers changing batteries and tarnished tags can cause unwelcome "thunderclaps of noise" through the speakers as you jump up and down.
Every Group Fitness Coordinator needs to know how to clear the connector crackles - it may save on a service fee!