The MonkMakes SSR is a low voltage solid state relay (no moving parts). This makes it super-easy to control loads of up to 2A at 16V from an Arduino, Raspberry Pi or other 3 or 5V microcontroller.
This modern take on the electro-mechanical relay can even be used for low frequency PWM to control the power to its load.
The dimensions of this board are: 52mm x 38mm x 12mm.
Check out more cool MonkMakes things here.