The warm in-ear monitoring sound of the IE 400 PRO with its rich, noticeable punch is the right choice for professionals who wish to take their accustomed studio sound. Even at high sound pressure levels, the IE 400 PRO reproduces its warm sound free from artifacts and distortion. With the newly developed TrueResponse technology, the dynamic driver measuring a mere 7mm generates tremendous resolution and prevents acoustic stress, even during long periods of use. Distortion, overlapping frequencies and resonance peaks which otherwise usually occur frequently are no longer a problem. The distortion factor has been optimized to a previously unimaginable 0.08%. It's miniature design also permits an ultra-compact construction which, thanks to the accompanying silicone and memory foam adapters, can be individually adjusted. This in-ear monitor is easy to handle and provides brilliant sound reproduction. Built to last under extreme stress, a secure and comfortable fit for hours.