Effective penis pump Handy pistol-grip Easy and comfortable use Cylinder with measuring scale Stiff & strong! There is definitely a reason why they've called this machine "Stiff & Strong", as that is exactly what it does to the penis. The pump is easy to use, creating a vacuum via a pistol-grip pump to adjust the pressure according to need. Complete length of cylinder 22 cm (with measuring scale). Insertion depth 21 cm, inner Ø 5.7 cm, outer Ø 6 cm. Ø of sleeve opening 2.3 cm (flexible). Material: ABS, silicone, metal.