EMics use windscreens. Windscreens need to be replaced on a regular basis and each instructor should use their own windscreen on the club's EMic for obvious health reasons. They can also be used with various other headmics such as those from Samson and other brands. Windscreens soften the 'plosive' vocal sounds and keep the wind out of the microphone if used outdoors.
Factory replacement EMic windscreens are only $20.00 for 8 - that's excellent value in anyone's language!