Hi @Alex_UJI1,
The non-locking 4" enclosure flanges use AS568-154 o-rings for the face seal and AS568-238 O-rings for the radial seals - the remaining spares of which are available here.
The precision machined tube ends of the locking enclosures mean the flange needs to be wider, but also that the tolerance between the tube and the flange is tighter, so the radial o-rings have a larger diameter but a smaller cross-section. The new locking 4" enclosure flanges use AS568-154 o-rings for both the face seal and the radial seals. Spare sets for the new flanges are available here.
No - the new radial o-rings would have too large a diameter to fit snugly in the old non-locking flanges, and the thinner cross-section means they may not seal correctly even if they did.
The o-rings we use are generally standard sizes, so if they’re not directly available in sets from us they should still be purchasable from a variety of online vendors, and potentially also from hardware stores.