Benelux Super 60 introduced in 1960. Sprocket range 13-26T, with a chainwheel difference of up to 4T, total range 17T. Was made up to 1969. Hope this is of some help have service diagrams etc for this mech somewhere.
Thats all for now. Keep those wheels spinning, in your memories if not still on the road. Be lucky Mick Butler Huntingdon UK.