This is vary rare genuine NOS pre-amp tubes. When it's gone, you will see it only on the used market!

NOS 12AT7 MULLARD WA CV4024 KQDD/K 

Military graded construction.

This batch was made during 1970s from the same Great Britain factory
All boxes are like new never opened!

Mullard was a British manufacturer of electronic components, including vacuum tubes, during the mid-20th century. They were known for producing high-quality tubes that were used in various audio equipment and amplifiers.