After many years of experience with AKG´s best sold head-worn microphones C544 and C555 it was time to use all the learnt facts and create a new generation. The output of this development is the brand new HC644 MD. It 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.