Fig. 2. Several styles and sizes of suction cannulas. Top to bottom: A flexible 6-mm cannula with two apertures of unequal size (the second aperture is much smaller than the first), a rigid 6-mm cannula, a flexible 8-mm cannula with double aperture, and a rigid 8-mm cannula. The flexible cannulas are typically longer than the rigid design. Not all flexible cannulas fit standard suction tubing because they may be designed to pair with a specific syringe design.