A Later PX4
PX4.org - Photo Gallery
Here is a later PX4, probably of 1950's manufacture. Note the change in envelope shape, with a reduced section top supporting the mechanical assembly via a mica disc and sprung lugs.
Here is a later PX4, probably of 1950's manufacture. Note the change in envelope shape, with a reduced section top supporting the mechanical assembly via a mica disc and sprung lugs.