It's a high-quality aluminium screw-in adapter.
 
Technical data:
Thread 1: 1/2 "
Thread 2: Dash 12
Material: Anodized aluminium
Angle: 90 degree bent
                                                    | Manufacturer: | Arlows | 
| Category: | INCH THREADS | 
| Item number: | AR3759 | 
| Angle: | 90° | 
| Thread: | Dash 12 | 
| Product weight: | 0,10 Kg |