I have a 135mm f5.6 Caltar-S II, which is a re-badged Symmar S, that I bought through this Forum after placing a wanted advert and it's a superb performer. It's equally as good as my 150mm f5.6 Sironar N, and 210 f5.6 Symmar S.

Both the Symmar S and Sironar N sold under the Caltar name and often sell for significantly less than the rodenstock & Schneied versions despite being identical in all but brand name, so well work looking out for.