The ring adapter screws onto the front of any lens and converts the lens' thread size to that of any other accessories such as filters, hoods, flashes, and lens converters. Made of aviation aluminum alloy. strong and light. Specifically designed for your camera for a snug fit. No wiggling or -threading. The first number is always the lens thread size and the second number is the filter size of the accessory. If the first number is larger, it is a step-down ring. If the first number is lower, it's an upgrade. Colour:black Material:Aviation aluminum alloy Package Contents: 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 1 x 49mm-37mm Step-down Ring 1 x 52mm-49mm Step-down Ring 1 x 55mm-52mm Step-down Ring 1 x 58mm-55mm Step-down Ring 1 x 62mm-58mm Step-down Ring 1 x 67mm-62mm Step-down Ring 1 x 72mm-67mm Step-down Ring 1 x 77mm-72mm Step-down Ring 1 x 82mm-77mm Step-down Ring Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.