Big Bronco Running Race Vest

Built for ultramarathon efforts where hydration and carry capacity matter, the Big Bronco is our pick for serious trail runners who need a vest that moves with them. The Max O2 Form chest system uses shock cord with controlled rebound to keep the pack stable without restricting your breathing. UltrAcool Light Mesh on the back panel cuts heat buildup and keeps the load comfortable mile after mile.

• 12L total capacity with front harness pockets built from 4-way stretch mesh — fits UltraFlask 550, Formula 250, Human 20 oz 2.0, wL Reservoir 2.0, or a collapsible bottle (none included)
• Compatible with a 2L reservoir (not included) for longer efforts where soft flask capacity alone won't cut it
• Max O2 Form chest system uses shock cord with tuned rebound — stable ride without squeezing your lungs on climbs or hard efforts
• UltrAcool Light Mesh back panel reduces heat and sweat buildup; sweat-proof back pocket protects your phone and valuables
• Developed with ultramarathon champion Jeff Browning — designed around real race needs, not marketing assumptions; available in Pitch Black/Red, sizes Small (35"–40") and Medium (38"–43")