Features: It can also be used with M42 lens to other bayonet body adapters, to achieve the effect of M39 to other bayonet body adapters. For changing mirrors or planting mirrors, convenient and practical. High quality aluminum alloy inner for tank, and outer layer of matte paint. Black attractive design,it is exquisite and compact. brand new and high quality Specifications: Material: Aluminum Alloy Color:Black Applicable lens: M39 lens Applicable models: M42 interface camera Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Lens Adapter Ring