Vee Mission: VRB.321 The Mission is for mountain bike trail riding or racing. Ramped and chisel shaped center and transition knobs set this tire apart from the others. Diamond shaped extra transition knobs provide great cornering. The tire is constructed with Folding Bead (FB), Dual Compound (DC) and 120 Treads Per Inch (TPI) casing material. As the knobs provide superior traction, we recommend this tire for mainly for Medium – Hard (M)-(H) conditions but it can be used for many trails.