Product Description For the most precise pumping possible, the Master Gauge Pump lets you see the exact pressure inside so you can repeat the perfect amount any time you like . This pump consists of a cylinder to insert your member into and a pump to remove air from the cylinder which creates a vacuum. A easy to grip pumper handle means you only need one hand to use this great tool, and the flexible hose won't kink or crimp. Finally, a super soft jelly TPE donut ring around the base of the cylinder provides an airtight seal that feels great as well. After you're done with this pump, the quick release purge valve makes it easy and safe to remove. Size 1 : pls see pictures Size 2: pls see pictures Cylinder inside length:8 (20.32cm) Diameter:2.5 (6.03cm)