Digital switch

So I'm not quite sure of the name of it but I figured this would be the best place to ask.

I used one of these before but I can't remember any of the information about it so here goes.

Essentially it's a digital button, arduino sends signal to it(HIGH/LOW) (on/off) which will essentially trigger a digital switch that is capable of handling MUCH more power. Thanks in advance! -Austin

Switching transistor or MOSFET or solid-state relay or relay...