This is the M4/Ø4.5 stylus adaptor #A-2054-4657. Stylus adaptors are designed to allow styli with different thread sizes to be built into stylus configurations.
| Thread mount | M4 |
| Overall length | 10.0 mm |
| Stem Diameter | 4.50 mm |
| Stem material | Stainless steel |
| Mass | 5.0 g |
