(!!!!!) (MATCHED QUAD) JAN-CW-231D Western Electric NOS 1953 (1.7/1.7/1.7/1.7ma) 1-2% matched
(!!!) (MATCHED QUAD) JAN-CW-231D Western Electric NOS 1953 (1.5/1.5/1.5/1.5ma) 1-2% matched
(!!!) (MATCHED QUAD) JAN-CW-231D Western Electric NOS 1953 (1.6/1.6/1.6/1.5ma) 1-2% matched
(!!!) (Recommended PAIR 1953) JAN-CW-231D Western Electric NOS 1953 (1.5ma and 1.5ma)
(!!!) (Recommended PAIR 1953) JAN-CW-231D Western Electric NOS 1953 (1.8ma and 1.8ma)
(!) (#1 231D Best Value Pair) 231D Western Electric NOS 1953 (1.8/1.8ma)
(!) (#1 231D Best Value Pair) 231D Western Electric NOS 1954 (1.6/1.6ma)
(!) (#2 231D Best Value Pair) 231D Western Electric NOS 1953 (1.7/1.7ma)
257A Western Electric engraved base NOS 1930's (6 in stock) (257A is a 231D with a top cap grid connection)
257A Western Electric printed base NOS 1954
231D Western Electric NOS 1953 (1.6ma)