ACS MainDrive External Headset - 1-1/8" Black. MainDrive External Headsets utilize forged steel cups alloy tops and cap with sealed mechanism bearings.
- TECH SPECS
| Defined Color | Black |
| S.H.I.S. Stem Clamp Diameter | 28.6 Threadless |
| S.H.I.S Lower | EC34 |
| Bearing Type | Cartridge |
| Crown Race | 30 |
| Color | Black |
| S.H.I.S Upper | EC34 |