The overall size for this cushion is 16" long x 18" wide with an inside U- Shape Hole that is 3 Wide x 4" Long
This seat provides two in one cushioning including a wedge and U shape cut out on the back to provide the ultimate comfort and support on any seating surface.
The coccyx cut out relives pressure of your tail bones when you're sitting for a long period of time.
The wedge shape comes in 2”, 3”, 4” and 5” thick to fit your best comfort to allow the correct sitting posture and circulation.