Here is the best 12AY7 microphone grade tube ever made: the industrial grade 6072 black plate 3 mica made by GE in their 5 star line. This tube is 1956 dated, has an excellent label and getter flash, and has been noise tested in a class A test fixture. It also tests balanced at 47 and 48 on our U-Test-M tester where 42 is minimum good. These are incredible tubes in any microphone that needs the 6072 or 12AY7, and makes a great V1 tube for your guitar amp, for extra cl...arity and later break up. Satisfaction guaranteed. IL residents pay 10% tax, outside of IL tax is determined by eBay for states collecting internet tax, no tax outside of the USA, but international buyers will be subject to import duty. We ship worldwide, all shipping is by first class mail only. TERMS OF SALE: Serious bidders only, please. Payment by PayPal is expected at auction close. A PayPal account is required to bid on this auction. We ship by first class mail to the name and address of the winning bidder provided to us by PayPal and/or eBay. We declare the full value on the customs forms for any international shipments. International bidders should be aware that first class mail cannot be tracked and that processing delays up to several weeks can occur in customs, which is beyond our control.