either i got a bad batch or they are utter shite! no offence. had them on a grind for half an hour practicing at home, wore down over half way, took them and and later i had a smooth rim so i tried them again, they lasted an hour at home then they sort of disintegrated. my sidewalls turned green, and it was in lumps like a rubber which you use to rub out pencil.
EDIT. i have three sets and all completely different. 1 light and translousant 2, opaque and a very dark green, and 3, dark and transloughsant.