eCostConnection Auto-Focus Macro Extension Tube Set for All Canon DSLR Cameras & a Microfiber Cloth 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) Tube Set Includes: 13mm, 21mm, & 31mm extension tubes Designed with all the circuitry and mechanical coupling Lightweight design Tubes can be used individually or in any combination to obtain the desired magnification