Description
Original Mesa equipment found in many earlier Mesa amps. Beam tetrode power tube known for its sweet, warm tone. This is the STR 420 slim bottle style. These tubes are compatible with 5881 and any 6L6.
CALIFORNIA PROPOSITION 65 WARNING
WARNING: Cancer and Reproductive Harm-www.P65Warnings.ca.gov.




John R. Littlewood (verified owner) –
These made my Mark IV sound new again. Bold and neutral just the way I like. I replaced a lightly used set of new STR 440 and there’s just something about the 420’s that brought back the girth. These are the tubes that came OEM in my mark IV.
DAVID M. (verified owner) –
currently installed 2 out of the quad I ordered in my mark 3 simulclass with el34’s in outside sockets’ also the square getter preamp tubes’ so far its sounding like it did back in the late 1980″s! mission accomplished