OWC Mercury Elite Pro Assembly Manual page 12

OWC Mercury Elite Pro Chapter 3 - Formatting
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Once you've selected the OWC device, you will notice the above change in
the Disk Utility application. Click on the "Erase" tab in this picture.
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You then need to name the volume that you want to format, and erase it.
Name the volume as you want, choose the Volume Format pulldown (Mac
OS Extended (Journaled) is default), and click the Erase button.