The Thunderbolt+ is Odyssey's tried and true Thunderbolt cranks, but now features updated graphics. The Thunderbolt+ is one of the most technically advanced crank designs on the market. Due to continued advancements in Odyssey's 41-Thermal processing and heat-treatment system, fatigue life has been increased by a massive margin. Bottom bracket sold separately. Proven 41-Thermal processed 4130 chromoly. Laboratory tested and team proven. Traditional sprocket interface. Updated open-ended spindle cap. New wedge cluster band with greater flexibility. Never-Wobble crank arm and spindle interface guarantee. Bottom bracket sold separately.