Coincidentally just received this from KEF,
Revolutionary sound absorption with MAT™
At the heart of the latest R Series is Metamaterial Absorption Technology (MAT), a highly complex maze-like structure where each of the intricate channels efficiently absorbs a specific frequency. When combined, the channels act as an acoustic black hole, absorbing 99% of the unwanted sound from the rear of the tweeter, eliminating the resulting distortion and providing a purer, more natural acoustic performance.
A bespoke 12th-generation Uni-Q driver array with MAT is found in all seven models of the R Series and delivers an incredibly detailed performance. It's the result of decades of accumulated in-house knowledge and all developments play a part in R Series' exceptional performance.
There are some new colours too.
Keith