Sennheiser Powering module for K6 Series capsules, powered by either a single 1.5 V AA (battery life 150 hours) or phantom power. On/off switch with LED indicator and bass roll-off (4.0 oz),
Sennheiser K6-P Powering Module - Newegg.com
Sennheiser ME64/K6P COMBO Cardioid microphone system