1. Step up rings, also known as adaptor rings:It allow you to use filters and accessories that are not the same size as your cameras lens. Lenses and filters come in a large range of types and sizes and unfortunately they don't always fit together correctly. Fortunately there is a step up or step down filter for just about any need. 2. How step up rings work:Step up rings provide a way to fit a larger diameter filter or accessory onto a smaller lens. The step up rings screws onto your lenses threading and provided a larger thread with with you can then attach other elements included more step up rings. 3. How step down rings work:Step down rings work in the exact same way but instead provide a way to attach smaller accessories and filters to larger lenses. 4. User tips:The typically the farther away from the lens you place a filter the worse the optics will be. It is always best to look for the thinnest adaptor ring that you can find as these will keep the filter close to the lens. 1. Include Step Up Filter Adapter Ring Kit(37-49, 49-52, 52-55, 55-58, 58-62, 62-67,67-72, 72-77, 77-82mm). 2. Include Step Down Filter Adapter Ring Kit(49-37, 52-49, 58-55, 55-52, 62-58, 67-62,72-67, 77-72, 82-77mm ). 3. Great tightness,no wobbling or cross-threading. Ultra-low chemical residues, attached to a solid. 4. Converts the thread size of your lens to the thread size of any other accessory (such as filters, hoods, flashes and lens converters). 5. Special aviation aluminum alloy, high strength, impact resistance, twist and pressure. Step-down ring package included: 1 x 37mm-49mm Step-up ring 1 x 49mm-52mm Step-up ring 1 x 52mm-55mm Step-up ring 1 x 55mm-58mm Step-up ring 1 x 58mm-62mm Step-up ring 1 x 62mm-67mm Step-up ring 1 x 67mm-72mm Step-up ring 1 x 72mm-77mm Step-up ring 1 x 77mm-82mm Step-up ring Step-down ring package included: 1 x 82mm-77mm Step-down ring 1 x 77mm-72mm Step-down ring 1 x 72mm-67mm Step-down ring 1 x 67mm-62mm Step-down ring 1 x 62mm-58mm Step-down ring