The following electric inlet plate covers can be used and may have been used in any installation for any brand including Modern Day. The round opening is just under 1-1/2 inch, mounting screws are just under 4 inches apart, and the plate fits into a 1-5/8 inch diameter hole in the mounting bracket in the wall. Any vacuum wall cover plate with two small holes (3/8 inch apart!!) can be replaced with one of the two following electric inlet types. Any of these valves can be used for new installations and retrofits as well.
Electric inlet valve covers have two voltage connections. One for low voltage wires (two screws on the backside) and one for 110 volts (on the front side of the cover). Electric valves can also receive other types of hoses including Stretch, Low Voltage, and Basic.
There are two types of electric inlets and they are not interchangeable.
Super Valve Electric Covers have a permanent 110 volt connection plug with wire leads.
Electra Valve Electric Covers hold a molded plug that is attached to 110 volt romex wire.