In a nutshell

Sennheiser MKE 40 cardioid belongs to MKE electret series introduced in the Eighties, with which Sennheiser was one of the first to reach high-standard miniaturization, combining sturdiness, stability in the long run and good sensitivity to temperature and humidity. MKE 40 remains the reference for cardioid lavalier microphones. The necessity of clearing inlets to obtain right polar pattern has led to bulkiness, so this microphone cannot be concealed on an actor. Its directivity has made it very popular on wired TV sets because of its insensitivity to back wave. Like all pressure gradient microphones, MKE 40 is wind and fast movement sensitive. So it should be used with supplied windscreen, at least to avoid plosives when it is placed right under mouth. MKE 40 is supplied with fixing accessories, among which is a magnetic clip.