The Siemens 3RF3320-2AA26 is a 1-pole solid-state contactor from the SIRIUS 3RF33 family, rated for 20 A in AC-1 duty at 40 °C ambient — that resistive-load rating is the one that governs continuous heating loads like ovens, heaters, or lighting banks. Control is via a 110-230 V AC coil, which means it pulls directly from a standard control transformer without needing a separate DC supply. Termination is spring-loaded (cage clamp), not screw — faster wiring in the panel, but verify your ferrule strip length against the terminal spec before terminating.
The package dimensions are 105 x 27 x 122 mm, so it fits a standard DIN-rail footprint with a 27 mm width — roughly 1.5 standard module widths. Mount it with clearance for heat dissipation; solid-state contactors generate heat proportional to load current, and the 20 A AC-1 rating assumes 40 °C ambient with natural convection. If the panel runs hotter, derate accordingly.