German BK-2H Blendkörper -Continued

A nice example of a BK-2H with the original seals.
(Thanks Scott for your help with this update.)
BK-2H Details

A modern o-ring as a substitute for a missing top seal.
O-Ring, #211 Buna-N, 70A Durometer, Black, 13/16" ID, 1-1/16" OD, 1/8" Width
This o-ring will also do nicely as a lower seal replacement.
(The small cap seal is approx. 12mm dia x 2mm thick.)
BK-2H Details

A sectional view showing how the seals fit & function.
Without the o-rings the glass and Bakelite will have an interference fit as the cap-ring is screwed tight and there is danger that the cap will crack.
So if you have a Blendkörper missing those seals, here's an economical way to improve things.
BK-2H Section