The Sightmark T-3 tactical magnifier is designed to magnify the image by three times when placed behind a Red-Dot, and with its high-quality 23 mm lens, the user can aim at more distant targets. Due to its light, compact design, the T-3 allows the user to switch between the enlarged image and the approx. Between the image of a Red Dot placed 10 cm away - depending on the situation. Product registration for extended warranty: https://support.sightmark.com/hc/en-us/requests/new?ticket_form_id=5585789283988