High-quality Golden Dragon vacuum tube for preamplifiers. Although I tested it once, it has been stored indoors without further use. I don't have a preamplifier now, so I haven't confirmed its operation. I believe it should work fine, but please consider it as junk just in case. - Brand: Golden Dragon - Model: Vacuum tube - Application: For preamplifiers - Features: High sound quality - Country of Manufacture: China Thank you for looking.