For VKF42.. butterfly valves · SQL321B.. Operating voltage AC 220 V, 2-position (SPDT) control signal · SQL361B.. Operating voltage AC 220 V, DC 0…10 V, 4…20 mA control signal · Optional auxiliary switch for SQL361B150…B2650 · Nominal angle of rotation 90° · Handwheel and position indicator · Built-in heating element to avoid condensation · Compatible with EN ISO 5211 flanges Use For operation of VKF42.. butterfly valves as shutoff and control valves in heating, ventilation and air conditioning plants.