Sennheiser Product Assistive Listening Devices HDA 200 General Description Closed dynamic audiometric headphones designed for extended high frequency testing. Features Very high passive ambient noise attenuation (based on PELTOR hearing protectors) Excellent repeatability of readings Suitable for high frequency audiometry, independent of positioning Soft, replaceable ear pads Padded headband for increased comfort Single-sided cable Design approved by the German Physikalisch-Technische Bundesantalt (PTB), a national standards organization similar to the British Standards Institute or the American Bureau of Standards) Delivery includes: HDA 200 headphones and HY 500 headband padding