Stay smart and dry Following up on the legendary performance of the C544 and C555, AKG has created the next generation of head-worn microphone, the new HC644 MD. This high-performance head-worn condenser microphone is the perfect tool for presenters in the corporate market but also ideal for sport applications like aerobics. More and more wireless systems in the low to mid-price range are based on 2.4 GHz technology causing nasty interference with microphones. The new HC644 MD is well protected against those problems. The main improvements of the new version are a smaller capsule design with a higher sensitivity, an exceptional RF shielding, a sweat-resistant design and the ability to fit to all major wireless systems on the market.