Explore Scientific 2x Focal Extender1.25in Barrel. 25in Barrel 2x Focal Extender increases magnification to any eyepiece with the same barrel size. The Explore Scientific 1.25in O.D. Barrel 2x Focal Extender provides generous eye relief and is especially great for eyeglass wearers. The Explore Scientific 1.25" Barrel 2x Focal Extender adds versatility to your telescope and pushes for high magnification. Specifications for Explore Scientific 1.25in O.D. Barrel 2x Focal Extender: Barrel Size: 1.25" Length: 96mm Width: 45mm Weight: 260 grams; 9.1 oz Package Contents: Explore Scientific 1.25in Barrel 2x Focal Extender 2x Focal Extender; 1.25-inch O.D. Fully EMD-Coated on all air-to-air lens surfaces with all lens elements edge-blackened