Compatible Cameras: Fits a wide range of Canon EOS SLR/DSLR cameras; including 5D; 5D Mark II; 50D; 60D; 20D; 30D; 40D; 350D; 400D; 450D; 500D; 550D; 600D; 1100D; 1D; 1D Mark III; Digital Rebel T4i; T3i; T2i; T1i; Xt; Xti; Xsi and Xs models Telescope Adapter: One end of the T2 T Ring is M42 female threaded and the other is Canon EF-Mount; you can attach your camera freely to a 1.25 inch or 2 inch focuser of telescope by using a appropriate T-Adapter which is not include Durable Construction: Made of high-precision metal with an anodized aluminum surface to ensure durability; the inner wall is designed with matte threads to reduce the effects of light scattering during observation Allen Wrench Needed: The inner ring is built into the T Ring and rotates freely as you unscrew the three screws on the T Ring with a 1.5 mm allen wrench to ensure that the lens is always pointing upwards correctly Manual Focus: Some short-focus camera or telescope's optical tube may not be able to focus quickly; so it is great for you to use telescope accessories which has M42 male thread such as the T2 extension tube and the barlow lens with M42 male thread Compatible Cameras: Fits a wide range of Canon EOS SLR/DSLR cameras; including 5D; 5D Mark II; 50D; 60D; 20D; 30D; 40D; 350D; 400D; 450D; 500D; 550D; 600D; 1100D; 1D; 1D Mark III; Digital Rebel T4i; T3i; T2i; T1i; Xt; Xti; Xsi and Xs models; Telescope Adapter: One end of the T2 T Ring is M42 female threaded and the other is Canon EF-Mount; you can attach your camera freely to a 1.25 inch or 2 inch focuser of telescope by using a appropriate T-Adapter which is not include; Durable Construction: Made of high-precision metal with an anodized aluminum surface to ensure durability; the inner wall is designed with matte threads to reduce the effects of light scattering during observation; Allen Wrench Needed: The inner ring is built into the T Ring and rotates freely as you unscrew the three screws on the T Ring with a 1.5 mm allen wrench to ensure that the lens is always pointing upwards correctly; Manual Focus: Some short-focus camera or telescope's optical tube may not be able to focus quickly; so it is great for you to use telescope accessories which has M42 male thread such as the T2 extension tube and the barlow lens with M42 male thread