First, I think the description at the top of the product description might be off.  Buried in the body of the page are more accurate numbers for the 88 Key cover.  The 7" H x 59.1" W x 23" D" description seems about right, as it fits my YPG-635 which is 55" W x 18" D (I didn't measure the height, but it fits with a little excess to spare).  I don't know that keyboards any larger would fit under the cover.