Features: 2X or 3X Barlow lens for telescopes, 31.7mm filter, also can be used for astronomical photography. for almost all telescopes which uses 1.25inch accessories and most brands of telescopes. Lens body is constructed of all black metal and is precision CNC machined for durability. Fully multi coated optical lens, providing you clear astronomical photography view. With for T/T2 (M42x0.75mm) male thread for T/T2 connectors, you can connect DSLR or SLR camera to telescopes easily via a for t ring adapter(T-adapter not included). Specifications: Magnification: 2X, 3X(optional) Lens Body Material: Aluminum Alloy Lens Material: Optical Glass Lens Coating: Full Multi-Coated Thread Specification: M42x0.75 T2 Thread Size: 1.25 inches (31.7mm) Size: As Pictures Shown Package Includes: 1 Piece 2X Barlow Lens or 1 Piece 3X Barlow Lens(2 Choices Optional) note: Please allow 1-2cm errors due to manual measurement,pls make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.