The circumference of the round disk portion measures 2 inches. The hook measures 2 inches. The complete extension from the wall (installed) is also 2 inches.
Yes, robe hook will hold a bath towel.
They are 2 inches out from the wall. See attached photo with ruler.
About 2 1/4” from the base of the circle mount.
Allen wrench is included with the robe hook
Specs are available for download in pdf, in the Product Overview, in the column to the right. I downloaded that without problems