Use directly with your camera. Simple Barlow Projection Use with your Barlow and camera. Eyepiece Projection Use your eyepiece in an extension tube. Extended Barlow Projection Use extension tube with your Barlow (Extended Barlow projection turns a 2x Barlow into a 3x or higher magnification). Telescope Mount Adapter: Features 1.25-inch mounting size on the telescope side. M42x0.75mm outer thread on one end and standard 1.25" (31.7mm) fitting on the other. Interior is fully threaded to minimize reflections. Threaded to accept standard 1.25" eyepiece filters. T-ring (with M42x0.75mm thread): Connects Nikon DSLR / Canon DSLR camera to the 1.25" Extension Tube and Telescope Mount Adapter. Extension Tube: M42x0.75mm outer and inner threads; one side fits T-ring, the other side fits Telescope Mount Adapter. Specifications: Material: Aluminum. Color: Black. Compatible with Canon EOS EF mount cameras (5D, 5D Mark II, 5D Mark III, 20D, 30D, 40D, 50D, 60D, 100D, 350D, 400D, 450D, 500D, 550D, 600D, 650D, 700D, 750D, 760D, 1100D, 1200D, 1D, 1D MkIII, Digital Rebel T4i, T3i, T2i, T1i, Xt, Xti, XSi, XS) and Nikon F mount DSLR cameras (D4, D4s, D3x, D3s, D3, D810, D800, D750, D700, D610, D600, D300S, D300, D200, D100, D7200, D7100, D7000, D5500, D5300, D5200, D5100, D5000, D3300, D3200, D3100, D3000, D90, D80, D70) with telescopes that have standard 1.25-inch eyepiece ports. Package includes: 1 x Telescope Mount Adapter, 1 x T-Ring, 1 x Extension Tube.