Opteka 25mm Auto Focus DG EX Macro Extension Tube for Canon EOS 70D, 60D, 60Da, 50D, 7D, 6D, 5D, 5Ds, 1Ds, T6s, T6i, T5i, T5, T4i, T3i, T3, T2i, T1i and SL1 Digital SLR Cameras Extension tubes are designed to enable a lens to focus closer than its normal set minimum focusing distance. Designed with all the circuitry and mechanical coupling to maintain auto focus and TTL auto exposure with Canon EOS SLRs Tube length: 25mm Glass-free; Lightweight 1 Year Opteka Warranty