Fig. 1. (A) A colon adenoma is not detected before the fold is hooked. (B) A colon adenoma is exposed by hooking the colonic fold with a transparent cap.

Fig. 2. Endoscopic hood with fixed distance of 2 mm (MAJ-1989, 1990, 1991, and 1992; Olympus Co.).

Fig. 3. Endoscopic image of a sessile serrated lesion (A) and its magnified image (B). The black rubber cap helps to keep a steady focal length during magnifying endoscopy.

Fig. 4. (A) The grid is drawn on a transparent vinyl paper with 1-mm intervals. (B, C) The grid paper is fixed at the inner circle of the colonoscopic cap on monitor. (D, E) When a polyp is detected, the endoscopist attaches the cap and measures the polyp size by counting on the external grid. (F) Polyp size is also measured with forceps. Adapted from Han et al. J Clin Med 2021;10:2365, according to the Creative Commons license.23

Fig. 5. (A) Single use caps (D-201-10704, 11304, 11804, 12704, 13404, 14304, and 15004; Olympus Co.). (B) Soft, transparent caps with two internal drainages, allowing for a clearer view field without fluid retention (Optimos Clear Cap, OCC-124, 140, and 150; Taewoong Medical).

Fig. 6. Endoscopic image showing foreign body removal procedure. Foreign body (pill foil) can be removed by placing the sharpest edge inside the cap for mucosal protection.

Fig. 7. Endoscopic image showing per-oral endoscopic myotomy procedure. Endoscopic cap can secure visual field and working space in the submucosal layer.

Fig. 8. (A) A ST hood with wide inner diameter of distal end. Therapeutic device can be inserted, while two drains pour out liquid inside the hood (DH-28GR, DH-29CR, DH-30CR, DH-33GR, and DH-34CR; Fujifilm). (B) A ST hood with asymmetrically tapered tip design prevents interference between hood and knife during endoscopic submucosal dissection (DH-40GR; FujiFilm).

Fig. 9. Single-use distal attachment with rim for performing cap endoscopic mucosal resection (D-402 and D-206; Olympus Co.).

Fig. 10. Over-the-scope clip system for applying clips on various lesions in the gastrointestinal tract (OTSC Clip; Ovesco Endoscopy AG).