Opteka Auto Focus DG EX Macro Extension Tube Set for Canon EOS 70D, 60D, 60Da, 50D, 7D, 6D, 5D, 5Ds, 1Ds, Rebel T6s, T6i, T5i, T5, T4i, T3i, T3, T2i 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 Contains three tubes of different length, a 12mm, 20mm, and 36mm Glass-free; Lightweight 1 Year Opteka Warranty