The Crydom Board allows up to 8 Solid-State switches switching 230 Volt Mains Power at 3.5 Ampere.
The logic inputs work with 5 Volts from an Arduino output. The switching goes on mains voltage zero-crossing, so produces little switching noise.
On the input side are leds indicating the status, the output side has fuses of 4 Ampere.
And yes, there exist "fake" modules with a mechanical switch.
CrydomBoard-files/CrydomBoard.jpg
Originally designed for the Oldelft "Simulix" Radiotherapy Simulator.
I connected the pins 2, 4, 6 .. 14, 16 on the bottom side, to have a common Line input terminal. (black)