It's a high-quality aluminium screw-in adapter.
Technical data:
Thread 1: M6x1
Thread 2: Dash 4 (7/16 - 20 UNF)
Material: Anodized aluminium
| Manufacturer: | Arlows | 
| Category: | UNF THREAD | 
| Item number: | AR7523 | 
| Thread: | Dash 10 Dash 6 | 
| Angle: | Straight | 
| Product weight: | 0,10 Kg |