Extension tubes are a perfect solution to allow ultra close focusing without sacrificing the optical properties of your lens. ProMaster Macro Automatic Extension Tubes are engineered for a precise fit and proper communications between your camera lens and body. The ProMaster 8819 Automatic Extension Tube Set for Nikon F mount cameras includes two tubes that can be used individually or in combination to gain the right magnification for your particular need.Set includes 12mm, 20mm and 36mm tubes in a neoprene storage pouch along with protective caps.