Product review (2 stars): Item is as pictured
This relay is exactly as pictured, the Fotek SSR-40 DA.  It has a metal backing plate, but a matching metal fin heat sink is sold separately.

It's very easy to drive, and I've had no problem driving it with 5V and sinking the current through a microcontroller. No driver required for an Atmega328P.

After about two years of extremely light, intermittent use, this relay has died on me. Regardless of input (open or closed), and regardless of the LED status light, the output circuit is always closed, causing the connected device to run continuously.  Things fail, but if this thing fails, and whatever you have hooked up to it can't run indefinitely, you have a real problem.