Upgraded and redesigned latest production from elite Shuguang China craft folks who have formed a new company to produce some of the best currently made tubes for audio. These look like and sound like old RCA tubes. Very neatly done 'two step' ladder grey coated normal sized plates. Glass envelope is heavy and built like a tank. Neutral full range sound that works well in Marshalls, Fenders and tube hi-fi. A nice 'all-arounder' preamp tube at an affordable price. I personally test and play guitar through every one of these tubes we sell. If I wouldn't use it in my own amps I won't ship it.