A portable Soundfield-style microphone for coincident stereo and surround recording. It is intended for location use and is physically smaller than the ST250 and MkV. Outputs are both stereo and B-Format. The unit can be powered by a mains unit or a battery pack (9-18V – 7W) which also runs an internal capsule heater to minimise condensation problems. Variable pattern mono, variable width stereo and post-directable surround can be obtained from the tetrahedral capsule array. The output levels from the control box are 0dBu balanced, +22dBu max. The microphone has uses in Ambisonic recording too.