6HV5A /6HS5 Beam Triode Tube. Designed as a high voltage regulator. MFR: Unbranded but probably made by RCA. SKU:6HS5. New old stock. No longer available for export.
VinylSavor: Tube of the Month: The 6HS5
Philco 6HS5 Vacuum Tube Made In USA NOS +Box | eBay