Kool-Stop have a photo of their green pads here: http://www.koolstop.com/images/ks-mttc_index.jpg
Those are not the type I have from SJS. My
green black pads are for V-brakes, like this:
Kool-Stop's compound chart is here, with explanations and applications: http://www.koolstop.com/english/compounds.html They say the green "is for 'ceramic' - This compound was designed for ceramic coated rims and is great in all weather conditions". They also market a black, labeled "R" and designated "Rigida - For Rigida CSS rims".
And going by Koolstop's listing they only have one green in this shape pad and they describe it as for ceramic
[EDIT] Stop-press!!! Just went and had a look at those pads again. Where are my glasses....... I was sure they were
green ??
No, the pads sold by SJS for Rigida CSS rims are
black, definitely black. Part no. KS-LPVBCSS