Thickened aluminum alloy, solid and lightweight. The front end is embedded with 0.75 thread, which can transfer the filter. Advanced hard plating technology, the entire is sanded black. CNC precision integrated precision manufacturing. Full frame with 2 inches, no dark corners. Specifications:
Condition: Brand New
Material: Aluminum Alloy
Weight: Approx. 56g / 2.0oz
Color: Black
External Thread: M42*0.75mm (Suitable for connecting the bayonet of T2 SLR camera)
Internal Thread: M48*0.75mm (Suitable for connecting with filter)
T-head Specification: 2 inches(Suitable for connecting astronomical telescope with 2 inch connector)
Matting: Internal Full Matting Thread
 
Package list: 
1 * 2" to M42*0.75 Adapter
 
Note:
This auction only for the M42 extension tube, others(the camera adapter, the filter and the camera)just for demo.