RCA 5751 TUBE as pictured, triple mica, black plate, in good condition (tested on my tube tester, where NOS tube normal ranged 105-110, min good=65, max good=120, tested tubes = 104/103 respectively, no short no leak) since this item is highly “MISHANDLING SENSITIVE” it is intending for professional (whom who know it well) and this selling is final (no return or refund) Please buy or bid accordingly. Thanks for looking.