A.
anwered by: canteau
It looks like some of the sites carrying the Tange Levin CDS are calling it the Levin ISO based on the crown race that's included.
There are 2 crown race versions of the Levin CDS Headset - 26.4mm ISO and 27.0 JIS. The 26.4mm headset fits most 1" threaded frames and the 27.0mm is mostly used on older Japanese frames and some track bikes.