Central Vacuum Standard Inlet Valve Plate White by Eureka - UNIVERSAL

Standard Inlet Valve Plate White by Eureka - UNIVERSAL

Center screw hole to center screw hole the measured distance in between is 3/3/4"

When you set this plate up in the wall you have some electrical connections- minor to connect the plate.
Then when you go to use your central hose the hose fits in and sets off the power for the central vac.