4 in x 2 in / 10.25 cm x 5 cm (cylinder)?The best head pump we have ever tested?it will blow your mind!? ? The American Pumpers AssociationEasy to use, incredible suctionAutomatic pressure control with the push of a buttonAuto start/stop buttonQuick air release buttonErgonomic hand-held controller with push button controlsEasy to read LED display measures PSI vacuum Compact seamless cylinderFlanged base for a secure sealBody safe donut includedOversized 10 in / 25.5 cm cylinder with 2.5 in / 6.25 cm diameter girthPC (cylinder) ABS with PU Cote (controller) TPR (donut) Silicone (hose)4 AAA Batteries Required (Not Included)