Professional Series Auto Focus Macro Extension Tube Set for Sony DSLR and Film Cameras - 13mm / 20mm / 36mm Magnifying your subject (making it appear larger in the viewfinder and in your pictures) 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 most Sony mount lenses Tubes can be used individually or in any combination to obtain the desired magnification 2 year manufacturer warranty