The low hump is a flowing curve from the floor board over the tranny. The high hump is an abrupt transition up approximately 6" over the tranny. The height of the cover is relative to the factory equipped transmission, however, if your tranny has been changed, you may have a low hump with a floor shift automatic transmission or an automatic in a factory equipped four speed tranny truck with a high hump.

I hope this helps.

Tony Smith