SSJ is screw mounted single phase solid state relay. Available in ratings from 15 to 45 amps CE, UL/c-UL, VDE approved There are three kinds of heat sinks optionally. There are three kinds of heatsinks optionally. Heatsink for SSJ-15 : Type RF-060 Heatsink for SSJ-25 / SSJ-45 : Type RF-120 Heatsink for SSJ-25 / SSJ-45 : Type RF-200