Elite Optima Diaphragm Set for Optima Aquarium Air Pump, 2-Pack Adjustable step-in dog harness is part of the Dogit walking apparel collection Fits Elite optima aquarium air pump models A805, A806, A807 Includes 2 diaphragm per pack Measures 1-1/9-inch length by 3-8/9-inch width by 5-1/5-inch height