Solid state relays just look like tiny black boxes with prongs sticking out the bottom (well all the ones I've ever seen were). A mechanical relay usually has a clear portion on the top where you can see the "guts" of the relay.

If it goes "click" it aint solid state. :smile: many of the mini mechanical relays are in sealed black cases.

The color of the case has nothing to do with it......If you look on the case it will say Coil Voltage, those are mechanical!!!