Easy to install, sits directly on toilet rim with the seat lid cover and seat raised into upright postion. Durable, lightweight and comfortable. Elevates the seat height 4-3/4". Four non-skid pads on bottom to keep in place. Easy to clean and transport. Perfect for home surgical recovery after a hip replacement or knee surgery. Holds up to 275 pounds. Dimensions Inside hole 9 5/8 x 7 ½ Ring 11 3/8 front to back, 9 3/8 wide Overall 15 7/8 wide, 16 7/8 front to back Goes hand in hand with Yunga Tart Reacher Grabber “Plucker’Up” reaching aid.