Ultraspire Synaptic Hydration Waist Pack FEATURES - The MBS belt at the back is compatible and interchangeable with a Lumen 600 front for a hydration and illumination combo; dual-sided adjustment for good sizing range with single speed hook access FLUID CAPACITY - 1 UltraFlask 550 mL included; BPA free, Phthalate free, and PVC free CONVENIENT - Angled minimalist bottle holster for easy right-handed access CARRY EVERYTHING YOU NEED - Hold essentials such as gels, energy foods, pills, electrolytes, a cell phone, keys, money, and light clothing or Z-poles RECOMMENDED USE - Racing and training with refueling stops every hour