My very pretty M600 Ruby Red Special Edition makes its 14th time into use in the 5 ½ years I have owned it.
An ok M600 14K medium nib - nothing really specially to say about this nib. Its writes well which is the main thing.
Iroshizuku momiji (Autum leaves) is lovely red that shades slightly from pink to red and exhibits some gold coloured sheen on 52gsm Tomoe River paper. A very well behaved pretty ink.
More pretty pink-red shading.