Height Adjusting Valve: The height of eyepiece can be adjusted from 67mm to 80mm. Diameter regulating valve, the diameter of eyepiece can be adjusted from 41.5mm to 44.5mm. Premium Quality: This photographic accessory is simple, practical and easy to install, made of aluminum alloy and can be used for a long time. Scope of Use: This adapter tube is equipped with adapter ring, applicable for FX mirrorless camera, which is helpful for visual photography. Application: This adapter tube thread M42x0.75 is suitable for T2 mount lens of camera, and T2 adapter ring to mirrorless camera for SERVICE: We take responsibility for our products and believe in their quality. Professional features and high reliability bring you a different experience and ensure the satisfaction of every customer. If you have any questions about our products, we will be ready to answer them for you.