These used tubes have been tested on a calibrated Hickok 752 or 752A. All tubes are tested for transconductance, internal shorts, defective elements and gas leakage. Tested and proven values of transconductance are written on the box in which the tube is sold and shipped. All tubes have been cleaned, pins straightened, wrapped in an internal paper cushion and boxed in new plain, white boxes. Listed price is for a single tube. All tubes are sold with a money back guarantee. Domestic sales: All domestic orders are subject to a minimum shipping charge of $8.00. Please add 50 cents for each additional tube. International sales: Shipping for international orders is higher than for domestic orders, please expect costs to be a bit more. I do charge a $5.00 handling fee for international orders, as these orders must be packaged with extra padding and wrapping to ensure they arrive to you unbroken. International orders valued at $50.00 USD or higher must be sent by a method that provides package tracking. If you have a specific tube you are looking for, but don't find it listed here, please feel free to contact me via the E-bay mail system. Thank you so much for looking over my products, and I look forward to doing business with you. Randy Withers