Expansion with the Omni SUI Nut Tool
The Omni Removal Tool (SUI Nut Tool) is used to remove the Omni from the top tube. The original Stromer price is 75 €. At Van Zijp technology the tool is available for €7.63.

Alternatives
1: The Mavic R-Sys hub tensionerM7 spoke wrench, incl. tire lever.
2: Take a wooden strip and two or four nails (e.g. picture nails) and make one.

3: If you have a 3D printer...the STL file is available here.
4: Removal is also possible with a 1.5 mm Allen key. To do this, press the omni slightly from above at the edges and insert the Allen key into one of the four recesses and turn clockwise.
> See also: "Stromer How to - Videos / Instructions" - 'OMNI C - Upgrade kit - Installation - 06/2018'