An “efneo GTRO” is a European made three-speed bottom bracket gear drive.
Cable engaged and technically very different in comparison to the KS3.
It is suitable for all single-speed bottom tubes but it can not replace an EVO KS3 gear drive (yet).
efneo GTRO three speed gearbox
Sorry, but I can’t figure out which way you mean that exactly…I’ll try this reply:
You can check the possible gear ratios here (including efneo):
Re: Gear ratios information about different models of Strida