Sea & Sea Focus Gear is designed for Canon EF 100mm f/2.8 Macro USM lens manual-focus by engaging the knob on the Sea&Sea NX Custom Flat Port or NX Zoom Port.
1 When using a combination of the NX custom flat port and the SX extension ring, set the teeth of the gear towards the end of the lens.
2 When using the NX zoom port, set the teeth of the gear towards the lens mount.