The Promatic Extension Tube Set includes tubes of 12mm, 20mm, and 36mm lengths, designed to fit a camera lens with a front diameter of 36mm. These extension tubes allow for closer focusing on subjects for macro photography, enabling photographers to capture stunning close-up shots with a smooth and precise focus. Made by the trusted brand Promatic, these extension tubes are reliable and high quality accessories for any photographer looking to explore the world of macro photography.