For BLX Wireless Systems, SM58 Dynamic Cardioid Capsule, Integrated Capsule Design, On/Off Power Button, Adjustable Gain Control, 14-Hr AA Batteries. It comes equipped with the legendary SM58 cardioid dynamic capsule an industry standard for vocalists and announcers. The capsule features a cardioid polar pattern that minimizes background noise and feedback. Its brightened midrange and bass roll-off deliver that sought-after warm and clear vocal reproduction. The built-in spherical wind and pop filter reduces plosives for clean and intelligible speech.