The Mega 17 inch Whoopee Cushion is our largest blow up whoopee cushion we sell and of course the classic gag to play on someone and it's a mega 17 inches. Place this under a cushion and when they sit down it will let out an Mega Embarrassing Sound. Your victim will never suspect anything! Use over and over. Measures 17 inches in diameter, make sure you do not over inflate.