The Hand Diaphragm Primer Pump (DP) is an air pump that creates vacuum suction in a centrifugal pump priming line and pulls water up into the pump to prime it. These centrifugal pump primers are popular for their portability and simplicity. DP7 DIMENSIONS 10 ⅞” x 9 ⁵⁄16” x 12 ¼” (Unit, Without Handle) ID: ¾ NPT OD: 1 ½ NPT Shipping Wt. - Approx. 21 lbs DP7 FOR PIPE SIZES: 4”, 5”, 6” The DP primer has a flapper check valve in the diaphragm and a disk check valve at the bottom of the unit. Air flows through the bottom check valve on the diaphragm up stroke then through the diaphragm valve on the down stroke. Diaphragm is actuated through a connecting rod eyebolt attached to a fulcrum handle bracket. The Protek Specialty DIAPHRAGM PRIMER PUMPS are centrifugal pump primers, ideal for use in irrigation, firefighting, liquid extraction, and fluid distribution applications. Compatible products : Centrifugal Pump, hand pump, skid. Common names : hand pump primer, centrifugal pump primer, suction lift primer, portable primer, centrifugal primer, centrifugal water pump primer, permanent primer.