Bower Auto Extension Tube Set for Canon EOS 7D, 5D, 60D, 50D, Rebel T3, T3i, T2i, T1i, XS Digital SLR Cameras (SXCAN) Mounted between camera body and camera lens to create distance between lens and film pane Retains autofocus function when aperture stays at f/5.6 or brighter for most Canon SLR models Extension tubes can be used individually or can be combined to obtain desired magnification Includes 13mm, 21mm and 31mm extension tubes Compatible with most Canon EOS models including: 1D/1Ds, 5D, 7D, 50D, 60D, T1i, T2i, T3/3i, XSi, XS, XT/Ti, 300D, 400D, 450D, 1000D