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.
Fits all tubes approximately 1" to 1-1/16" diameter (23mm to 28mm), including metal 12SC7, "slim" 5Z4, 6EW7, metal shell 6F6, 6J5, 6R7, 6SJ7, "slim" 6SN7, metal 6V6, 6X5.*
* 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.