The Xit Pro Series auto-focus macro extension tube set is specifically designed for Canon DSLR and SLR cameras. It includes 3 tubes which can be used individually, or in combination to achieve the desired magnification. It is designed with all the proper circuitry and mechanical coupling to maintain auto-focus and TTL exposure with most Canon mount lenses. Perfect for flowers, insects, coins, stamps, and any close-up shots you want to take. It includes 13mm, 21mm & 31mm tubes. Designed to enable a lens to focus closer than its normal set minimum focusing distance. Magnifying your subject (making it appear larger in the viewfinder and in your pictures) Designed with all the circuitry and mechanical coupling to maintain auto focus and TTL auto exposure with most Canon mount lenses Lightweight design Tubes can be used individually or in any combination to obtain the desired magnification