A square profile provides a solid, consistent feel across the knobs. Modified knobs on the shoulder and center improve braking performance and traction on hard surfaces. EXO equipped models feature Maxxis` EXO sidewall protection which help prevent puncture from sidewall abrasions TR - Tubeless Ready - sealant required Tubeless 29x2.3 622 TBLS - Fold Bk/Bsk 60 920 60 EXO/TR No