2D21 Thytron Vacuum Tube. Designed to be used in relay and grid-controlled rectifier applications. MFR: RCA, Westinghouse, Sylvania, GE, Tung Sol, National. SKU: 2D21. New old stock. No longer available for export.
2D21 National Eletronics NOS NIB electron tube red box made in England, For Old Electronics, Mounting Type: Circuit at best price in Mumbai
1 TUBE 2D21 / PL21. RCB161 | eBay
RCA 2D21 5727 Thyratron Power Radio Tube VT-0686 - Etsy France