The Book Of Inventions Ian Harrison National Geographic Engraved 6PNPC This lot of four new

This lot of four new old stock

new in box US-made 12K7GT tubes tested to spec on our Paul Hart-calibrated TV7/U

There were no shorts or gas and they test as follows:

There is also a shield between the triodes for reduced cross talk

The Book Of Inventions Ian Harrison National Geographic Engraved 6PNPC This lot of four newThis gilt edge, copiously illustrated book is in excellent condition. The spine is in fine shape with no loose pages and APPEARS to be leather bound. MOST FORMS OF SHIPPING EXCEPT MEDIA MAIL ARE AUTOMATICALLY INSURED UP TO $100. ETSY PURCHASE PROTECTION COVERS ITEMS UP TO $250 IN VALUE. IF AN ITEM IS MARKED "DELIVERED," AND YOU HAVE NOT ACTUALLY RECEIVED IT, THE FIRST STEP IS FOR YOU TO CONSULT YOUR MAIL CARRIER TO GET THE EXACT COORDINATES OF THE