This Lot of Four (4) Type 27 globe glass tubes was tested on our Jackson 648 measuring: Tube One: 110% (EVEREADY RAYTHEON ER227 engraved on base; original retail label on glass) Tube Two: 106% (Tung-Sol engraved on base with code 8-2; 27 stenciled atop glass) Tube Three: 98% (Gold Seal Y-227 engraved on base; label on glass) Tube: Four: 93% (Majestic G-227 engraved on base) Good range is between 70 - 130 (70% - 130%) on the Jackson 648 tester. Tubes are tight on bases. I wish I could tell you how they sound, but I do not have a preamp that can run these. I have a number of Type 27s in my store, including matched pairs, please view to see if any fit your equipment needs. View my store for more varieties of tubes for your equipment. Tube ships via United States Postal Service (USPS) First Class Mail with tracking for domestic U.S. sale; Priority Mail is an option. International orders ship via USPS First Class International Mail Package; tracking and insurance can only be provided if you purchase USPS Priority Mail International service. Package weighs fifteen (15) ounces. Combined shipping always welcomed. TUBES ARE GUARANTEED GOOD AND IN WORKING ORDER AT SHIPMENT. TRANSIT VIA POST CAN DAMAGE TUBES. THIS IS NO FAULT OF OURS BUT THE THIRD PARTY ENTITY THAT IS DELIVERING ITEM(S) TO YOU, I.E, USPS, UPS, FEDEX, YOUR NATIONAL CARRIER IF INTERNATIONAL, ETC. PLEASE INSURE THEM! WE CANNOT GUARANTEE FAILURES ON YOUR EQUIPMENT AFTER POWER UP AS THERE IS NO WAY TO ASCERTAIN HOW TUBES WILL INTERACT WITH YOUR ELECTRONICS; NOR IS THERE A WAY TO DETERMINE WHETHER THEY MAY HAVE FATAL FLAWS IN TUBES THEMSELVES! THESE ARE USED VACUUM TUBES AND TIME MAY HAVE TAKEN A TOLL ON THEM OVER THE MANY YEARS SINCE THEY WERE MANUFACTURED. WE CAN ONLY TEST FOR THE PARAMETERS MENTIONED ABOVE IN ONE OR MORE OF THE FOLLOWING EQUIPMENT WE USE FOR MEASURING: TV-7/U, JACKSON 648 MAXI MATCHER 2.