Yes... that is a surge suppressor!
I call these by two names, they are interchangeable: trip & boom or touch & fry! You trip on the cord, it goes boom due to bad strain relief or you touch it and complete a nice ground fault circuit.
The sad thing is they make boxes DESIGNED for use with cords, they have the needed strain relief.... why doesn't anyone use them instead?
and it looks like it's @ the end of the line to only protect itself, none of the others
