Luman nebula Filter 1.25 "inches A nebula filter reduces the brightness of the nebula and improves contrast so that greater detail can be observed on the planet surface. The filter has threads on it which screw into the bottom of the eyepieces. ? Brand: Luman Origin: China Material: metal frame + optical glass lens Color: Red Size: 1.25 inches (31.5mm) Screw thread: Metric screw thread Net weight: 9g