Trick thefts are an increasing danger, and especially elderly people are often defenseless against the audacity of uninvited visitors. A door viewer is therefore a fundamental requirement for your decision on whom to open the door to and whom to avoid. ABUS door viewers are characterized by wide-angle optics, ensuring you can see who is standing at your door. The extension piece for the ABUS door viewers 1200, 2200, 2203, and 2300 is used whenever the door is thicker than 53 mm. An extension piece covers an additional 10-17 mm of door thickness. You can also use multiple extensions in succession, but the viewing angle decreases with increasing length.