As the mid-sized option in Gregory's mountain biking-specific collection, the Women's Amasa 10 Hydration Backpack is your best bet for half-day rides. It can hold hydration reservoirs as large as three liters, and there's still space for snacks, layers, and essential tools and a spare tube. Gregory's Shift RS suspension system includes light foam with spacer mesh that assures the utmost ventilation, and the padded waist belt moves with your hips for long-lasting comfort.