This is a quartet of four metalbase 6V6GT-S (aka. 6P6P) "Summer-Of-69 Special" tubes. They are Premium Matched by TAD NOS-tubes made in the year 1969.
NOTE: these tubes are selected NOS, means new (unused) old stock. They are typically 50 years old sleepers. Signs of age, such as faded colour of phenolic base or print markings, flash rust on metal parts or slightly opaque glass might occur.
