The video says: as568a from hxxp://www.mcmaster.com/#as568a-o-rings/=e0oykz (select 008) -> it says outer-dim is 7.9mm and inner is 4.7mm and assuming they have round cross-sectional shapes
I've been looking around as well.Simply Bearings seems to have pretty good prices for the sort of quantities we want, and reasonable p&p.
set the filter "Inside Diameter" on the website from *Soarer* to 4.7mm, it gives two o-ring product, the closest one to the mentioned o-ring in the video is the one with the outside diameter of 7.9mm. I think this is beefier than the 7.54, don't know if it would make a difference tbh.
Haven't got my mechanical keyboard yet, but if I get the Filco over the RealForce and I end up bottoming out then I may just get a set of the o-rings :-). Weird thing is if you order 1x100 they charge £25 though iff you order (50 x 2) would only cost £16 :laugh: => total + shipping inc VAT (£21.00)
Edit:
These guys ship to UK, 125pcs:
hxxp://www.wasdkeyboards.com/index.php/products/keyboard-accessories-2/cherry-mx-rubber-switch-dampeners.html