This kit from Zeronoise is part of a two-piece system for converting a closed face or fixed boom helmet to an earplug style intercom. This portion contains the microphone, nexus connector, and the connector for the earplug portion.
Primarily designed for full-face helmets. Only male nexus connectors are currently offered – you will need an adapter for stilo intercoms.
Earplug portion available here: ZeroNoise Foam Earplug Kit