IFI - NOS 5670 (6922) Vacuum Tubes (Pr) Compact, super-low-noise versions of 6922/6DJ8 tubes Computer-matched and thermally revived Machine-fabricated adapters that reduce heater-supply noise and ensure great fit in any 6922 audio component Each valve is hand-selected and inspected to ensure the internal structure has not been compromised by the long storage Burned-in for 48 hours before matched by computer