1、M42 Thread: This telescope extension tube has a thread of M42x0.75 and is suitable for camera T2 bayonet lens, the T2 adapter ring can transfer to SLR for SONY. 2、Height Adjustment Valve: The M42 thread telescope tube has a height adjustment valve to adjust the height of the eyepiece from 117mm to 149mm. 3、The Projection and Focus Adapter Consists of Two Parts: The projection part is used with the eyepiece to achieve long focal lengths for small objects, and the focal length adapter is used without the eyepiece to take pictures of the entire moon, gas nebulae or galaxy using the telescope's focal length. 4、Scope of Application: Equipped with adapter ring for SONY, is suitable for SONY single lens reflex camera, which helps with visual photography. 5、Can be Used for a Long Time: This telescopic adapter ring is simple to install and the aluminum alloy material makes it hard to damage.