Washing machine safety shut off valve question

I am installing washer and I want to add safety automatic shut off valve.
I found this:Onsite Pro FS3/4H90 Washing Machine Valve Shutoff Kit


Does the kit include all I need? I have 20 amp circuit in laundry. I see people buy power relay with the valve but I am not sure if I need it.
[h=1]Furman MP-20 Power Relay Accessory, 20 Amp, Two Outlets, Remote Turn-on from Momentary or Maintained Contact Switches[/h]Thank you Michal

The Floodstop valve turns off the water supply lines (hot & cold) so if one of the supply hoses burst and the Floodstop detects any water leakage (via its sensor that is placed on the floor) you are protected against significant damage.

The Furman control provides extra protection for cases when the washing machine drain hoses splits or falls out of the drain; if the Floodstop detects any water it sends a trigger signal to the Furman, which shuts off power to the washing machine so minimal water leaks from the broken drain hose.

So decide how likely a burst drain hose is and base your purchasing decision on that.