mary ,google machine embroidery mega hoop & it will give u several different brands of machines with sizes of mega hoops *4u
If it is a Janome gigahoop, the design area of mine measures 23 x 20 cm. It's quite big. I've never used it but the machine/software splits the design and stitches it out in two halves, that is you turn the hoop to stitch the second half of the design. (worked out from the instructions)
Well said lbrow, was just going to add that, looking at the words, mega, giga, they get so confusing between the different machine brands.