U5 Osram balloon CV3743 FIRST ever made rectifiers pair 1929 super rare

Description

The U5 was one of the first if not the first full wave rectifier and was introduced to the public in 1926, almost 100 years ago!

One of the feature of this valve is to have inverted filament, something the MO-V made proudly.

You can clearly see then Anode is flat showing no coating or anything named Dark Plate!

This was then original design for all rectifiers that follow suit.

For sale a pair of Osram balloon U5 rectifiers with their tatty boxes but still alive!

Both U5 Osram have been tested at 100% emission and working order.