6021 GE 5 Star Rated NOS "D" getter halo 1957 matched pair
Subminiature Tubes: The Future of Audio! - Effectrode
Subminiature Tubes (6111, 6021) on 9-Pin socket (6DJ8, ECC88, 6922 etc) « FET Audio | Hi-End Audio & Electronics
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6021 TUBE | eBay
6021 Sylvania Medium Mu Twin Triode Tube. Designed for use as an amplifier in high and UHF circuits. New old stock. No longer available for export. MFR: Sylvania. SKU: 6021.