HoopMaster 4.25 x 13" Mighty Hoop for Melco.  The inside dimension of this hoop is 4 1/4" x 13" (4.25x13", or 108x330mm)

Actual sewing area depends on brand of machine approximately 3 1/2 x 12 1/4" (3.46"x 12.21" or 88 x 310mm)