Extension tubes are a perfect solution to allow ultra close focusing without sacrificing the optical properties of your lens. The ProMaster 8826 Automatic Extension Tube Set for Canon EF / EF-S mount includes three tubes (12mm, 20mm and 36mm) that can be used individually or in combination to gain the right magnification for your particular need. Protective dust caps and a handy neoprene storage case are also included in this premium kit.