This Hoop will only fit on large format Barudan and a few Tajima machines. If your machine can hold a 460x434 Barudan hoop, or a Tajima 510x450 (must be a single head machine), then this hoop will work on your machine.
The Tajima will need the 600mm 1" offset adaptor brackets.

 

Your brackets may look different than the picture

The inside dimension of this hoop is 17 1/4" x 16 5/8" (17.275x 16.61", or 438x421mm)

Actual sewing area depends on brand of machine
Approximately 16 1/2" x 15 7/8" or (16.486 x 15.822 - 418 x 401mm)