As the most aggressive tire in Teravail's lineup, the Kessel excels on loose, rocky, steep trails where traction is the top priority. The tread pattern is familiar to us, using a combination of tall angular lugs that dig deep to find traction in loose terrain, with the center lugs being ramped to reduce rolling resistance on hardpack. Aggressive siping is found throughout, increasing the tread surface area under load to provide better grip in all conditions. The Durable casing uses a bead-to-bead protective layer to help fend off punctures without adding too much weight, and we've found it to be great option for most trail riding. Gravity enthusiasts and hard-chargers who aren't too concerned with weight will be better suited to the Ultra-Durable casing, which adds an additional 1/2-ply reinforcement to the sidewalls, extra puncture defense under the tread, and butyl inserts to improve sidewall support and durability.