A Survey of Foster 443742 Variants: Inside Photos
The biggest physical differences are in the Fostex branded headphones. Interestingly, they've got damping material in the cups, but the TH900 headphones, to my eyes, have the most noisy impulse response. They also are the only ones with a circular earpad hole...I may try to swap the TH900mk2 pads with the E-Mu pads and re-measure. I'd bet the noise is coming from resonances in the earpad chamber.
Anyway, here for your viewing pleasure is the inside look.
E-Mu Teak (Shown in Ebony)