This Hakko Temperature Control Key Card B2972 is a must-have for those who own Hakkko FX-951, FR-803B/802, FM-205/204/203 soldering equipment. With this key card, you can easily control the temperature of your soldering equipment and achieve the perfect soldering results. This control card is for the compatibility of Hakkko FX-951, FR-803B/802, FM-205/204/203.