To replace a malfunctioning diaphragm on the Hypro D115 or D135 pumps, use this 9910-KIT1721 D115/D135 Diaphragm Kit. Prevent further mixing of your sprayer liquids with the oil in the crank case with your new kit, which includes everything you need to do to switch out faulty parts. It contains three main diaphragms, an accumulator diaphragm, and six o-rings.