Your moms size
You need 3/8 Allen key.
I believe that is a 7mm Allen.
It takes a 7mm allen wrench.
An allen wrench is sometimes referred to as a hex wrench or hex key.
2006 lincoln navigator requires a 7mm hex to remove brake caliper
7mm Allen wrench
Allen Screws.
There is no Allen wrench, I believe it is 14 mm open wrench.
An Allen wrench is a hex head wrench - a screwdriver with a handle and hexagonal head at right angles to each other.
No they are NOT the same.
James Van Allen didn't invent the Allen Wrench it was William G. Allen in 1909-1910 of the Allen Manufacturing Company of Hartford, Connecticut.
To fasten and unfasten Allen screws and bolts. These fasteners have a hexagonal slot in the top into which the Allen wrench or key fits.