Roadmaster Mountain Bike Handlebars

[Dyno6942]

I just inherited a set of his and hers Roadmaster Mountain Bikes. The previous owner put "apehangers" on the men's bike. I want to switch these back to "lowrise" bars, but I am not sure what size hole is in the stem. Does anyone know what size I need to order?
Best wishes to all!
Dyno

[DaveM]

should be 1" (25.4 mm)

[Dyno6942]

Thank You! I appreciate your help.
Don