The Mitas 90/100-21 C-19 is an extreme enduro, MX and cross country tire available in three different rubber compounds. The C-19 is a great lightweight tire that excels in wet root and rock environments. Red, green and yellow stripes indicate the tread compound with red being the hardest and green being the softest. Green stripe tire indicates a softer carcass and soft tread compound for extreme enduro or cross country competitions on harder terrains. The tread compound is softer than the yellow-stripe (Super) version and designed for harder terrain.