Our pricing for this product is the "MAP Pricing." This means that the prices shown here are the "minimum advertised prices" permitted by the manufacturer. Because these are already the lowest prices possible, the additional incentives usually available under "Frequent Flyer" program do not apply to this item.
For all tubes approximately 1-3/4" to 2-1/8" diameter (45mm to 54mm), including 1610, 2A3 (RCA, Sylvania, Tung-Sol, Brimar), 26, 274B (Western Electric), 350B, 3D21A, 45 (RCA, Sylvania, Tung-Sol), 572-10, 5998, bulb-shaped 5R4-types, 5R4WGA/B (Tung-Sol), bottle-shape 5U4G, 5V4, 5Z3, standard and wide 6550 (E-H, GE, Philips, RCA, SED, Svetlana, Sylvania, Tung Sol), 6550A, 6550C, bulb-shape 6AS7, 6B4, 6B4G, 6BY5/G/GA (bottle-shape), 6C33C (upper portion of tube), bulb-shape 6F6G, bulb-shape 6L6G, 71A, 80, 807, 811, 814, C327 ("bulb" 27), CX4, bottle-shaped octals like CV181/ECC32, CV378 (Mullard), EL37, bottle-shaped GZ32, GZ33, KT66, KT88 (E-H, EAT, GEC, Gold Lion/Genalex, JJ/Tesla, SED, Shuguang, Sovtek, Svetlana), ST-14 bulb, ST-16 bulb, U52.*
* Tube diameters and shapes sometimes vary. To estimate your tube diameter, just place a wooden or metal ruler against the side of your tube and "eyeball" the size. Or measure the circumference and divide by pi (3.14). Tubes are listed above by widest diameter of the bulb glass; on some bottle-shaped tubes, damping instrument can be placed around the "neck" of the tube, where the neck meets the shoulder, allowing use of the next-smaller size damping instrument.
For tubes that fall in-between UltraSonic sizes, smaller size is the default recommendation for straight-sided tubes (though either size will work); for bulb-shaped tubes, larger size is the default recommendation. Titanium C-rings can be bent to a somewhat smaller or larger diameter to accomodate variation in bulb diameters.