So these lambskin leather ear pads made to fit the B&W PX7 for $6 USD each (shipping other fees are separate and will vary by your shipping destination) each came recently and I must say that I am rather satisfied with the fit, comfort, and lack of change in the overall sound signature:
https://www.alibaba.com/product-det...mbskin-Replacement-Ear-Pad_1600525864678.html
The stock ear pads already had a tiny tear on the bottom-left inside edge of the right side, and I grew tired of the pleather feel so they needed replacement to go with my slim headband cover. Comparing the inside fabrics between the lambskin and stock ear pads, the lambskin leather ear pad's inner fabric was weaved in a diamond-like hexagonal pattern, like the skin-contact-fabric of the stock hybrid Hifiman Edition XS ear pads, whereas the stock ear pad fabric weaving is more microscopic with tiny concave dots in a more randomized lining. Thankfully, I do not really hear any audible differences between the ear pad fabrics or the overall sound signature of the PX7, but the ear pad depth is another different consideration.
The lambskin ear pad openings are no more than 10mm wider than the stock ear pads in any given direction (about 4mm-7mm, really), but the depth is about 20%-25% thicker than the stock ear pads, leaving more lambskin leather sagging around the ear cup edges. Even with the lambskin ear pads and slim headband cover on the PX7, the stock hard-shell case still zips up completely, just a little more snugly. Of course, since you have to adjust the headband gimbals back completely inside to put the PX7 into the stock hard-shell case, you need to slide considerably more headband gimbal space to ease on the clamping and have the ear pads rotate more evenly along your ears and head. It will take a little more time, but the extra clearance from the lambskin ear pads is a definite welcome in my book.
I say this after no longer feeling a faint touching sensation from the lower part of the inner ear cups on my ear lobes with the lambskin leather ear pads. Finally, I have a full-size ear pad feeling with the PX7 all around my ear and it is wonderful. But what about the overall sound? Sure, the overall sound signature sounds extremely similar, but the depth of the sound signature has changed a little bit with the ears resting a little further back from the drivers. With the stock ear pads, I could not tell much of an audible difference between no/high/low/auto noise-cancelling (or NC) modes. With the lambskin ear pads, I need to press the volume increase button once to match the stock ear pad amplification on no-NC mode, whereas the volume stays the same on high-NC mode. You typically do not need to change the volume on low-NC and auto-NC modes, but your environmental situation may change that.
Those are the differences between the lambskin leather ear pads linked above and the stock ear pads, which are overall a great welcome for my listening preferences. Even with the stock ear pads, I do not think that I could wear the PX7 for more than 5 hours from my ear lobes feeling the bottom-inner-ear-cup portion all of the time. With the lambskin leather ear pads...yeah, that rated 20 hours of battery life is very understandable. As my ears become more attuned to PX7 sound with the lambskin leather ear pads and slim headband cover on them, the overall sound has become more airy, yet still as visceral as B&W intended them for the listener.
For those who fly coach or econ all the time, these lambskin leather ear pads have to be very warm welcome, especially on very long flights. I also have used the shortest cable to this USB-C three-pack to charge my PX7 and they go from the first instance of "low battery" to 100% full in roughly about two hours (INIU makes a bunch of different USB-C cables, but these are the exact ones that I used to get that re-charging result):
https://www.amazon.com/INIU-Charging-Braided-Compatible-Samsung/dp/B07XYJBQ5Y/ref=sr_1_3
https://www.amazon.co.uk/INIU-Charger-Charging-Braided-Samsung-Black/dp/B09DKB9PKK/ref=sr_1_5
I hope this all helps and happy listening with your B&W product.