(!!!!) (Single 1955) 12AU7 Brimar UK NOS gray ribbed plates "D" getter halo 1955 (8.2/10.4ma)

1 low noise tube) 12AU7 Brimar UK NOS narrow gray ribbed plates "D" getter halo 1955

1 section) 8.2ma Gm=1900

1 section) 10.4ma Gm=2300

Good Ma range 8-10ma

Good Gm range 1800-2200