The usual term colonoscopy usually refers to a colonoscope, which is about 130 to 160 centimeters in length and about 1 cm in diameter. Colonoscopes are theoretically divided into colonoscopes, small bowel scopes, proctoscopes, etc., with different lengths and diameters. Colonoscopes are about 130~160 cm in length and about 1 cm in diameter. single-balloon small colonoscopes are 200 cm~220 cm in length and 9.2 mm in diameter, and double-balloon electronic small colonoscopes are 200 cm in length with an outer diameter of 8.5 mm. proctoscopes have a diameter of 4 cm, and are available in 12 cm, 15 cm, and 20 cm lengths. Colonoscopy usually takes 15-30 minutes and biopsies are taken for pathology if necessary. Most patients can undergo the procedure while awake, or under anesthesia if they are sensitive to pain. As different lengths and diameters of colonoscopes are required for different examinations, it is important to consult your doctor for details.