The 6CB6A (along with its standard 6CB6 variant) is a 7-pin miniature sharp-cutoff pentode engineered primarily for high-gain intermediate frequency (IF) and radio frequency (RF) amplifier service in television receivers and communications equipment. Introduced in the 1950s, its high transconductance and low interelectrode capacitance make it exceptionally effective for wide-bandwidth video amplifier and high-frequency gain stages. The "A" suffix designates a controlled heater warm-up characteristic designed for series-string tube circuits. Operates on a 6.3V heater and fits standard 7-pin miniature sockets. Available NOS and tested used.