TheTechLounge posted a review on the Sennheiser PXC 450 Headphones

Sennheiser creates some of the best audiophile headphones you can buy, but they also manufacture professional headsets for the aviation industry that feature an active noise-canceling technology dubbed NoiseGard. Today we'll take a look at a pair of their high-end consumer headphones, the PXC 450, that includes the same NoiseGard technology as used in some of the
professional aviation models.

Sennheiser PXC 450 Headphones Review