Adapter Camera For Alpha SLR 42mm Mounting Sleeve For Scope : Designed for digital SLR digiscoping; connect to observation telescope to shoot comfortably and easily; Universal photo sleeve with M42 threads on both ends fits all 42mm diameter glasses; so measure the eyepiece to make sure it will fit your specific scope as it is a made unit Adapter T2 : A useful accessory allows you to attach the camera to the Alpha SLR camera to the telescope, camera and other astrophotographic accessories How to use: screw in the adapter adapter , then screw the entire adapter into the DSLR/SLR camera to connect to the telescope/microscope the hollow side of the sleeve does not affect the adjustment of the focusing knob Specification: Material: Aluminum Length: 2.76 inch/7 cm Total length: 3,11 inches / 7,9 cm Diameter: 1.77 inches/4.5 cm Thread: both adapters are universal thread M42x0.75; black Mount: for Alpha SLR camera (Compatible DSLR A55, A55, A77, , , A230, A290, A300, , , A390, , A500, , , A700, A850, A900 and most SLR bodies for ) contains: 1 . Adapter camera lens with T ring for Alpha SLR 1 42mm adapter for telescope mounting