Built for fast-moving day hikes and everyday versatility, the Gregory Inertia 18 H2O combines streamlined organization, all-day comfort, and integrated hydration into one lightweight adventure-ready pack. Whether you're chasing miles on local trails, tackling warm-weather summit pushes, or commuting with outdoor gear in tow, this compact daypack keeps essentials organized and water always within reach.
At the heart of the system is the included 2L Hydro reservoir, housed inside a dedicated zippered hydration compartment for quick access and efficient refills. The Easy-Fill handle and leak-proof bottle-style cap simplify trail hydration, while the inline hose quick-disconnect allows refilling without rethreading the hose through the harness. Gregory’s SpeedClip hydration hanger creates a fast, one-handed connection system, making setup smooth and frustration-free before you hit the trail.
Comfort stays front and center thanks to the perforated 3D foam backpanel and breathable shoulder harness, both engineered to promote airflow while maintaining supportive carry. The pack transitions seamlessly between trail days and everyday use with practical storage options including zippered security pockets, mesh bottle storage, trekking pole attachments, and a removable hipbelt for customizable support. Lightweight, organized, and hydration-ready, the Inertia 18 H2O is built to keep pace wherever the day leads.
Features
- Lightweight 18L hiking daypack with included 2L Hydro reservoir
- Dedicated hydration compartment with 3/4 zippered access
- SpeedClip hydration hanger enables quick one-handed reservoir attachment
- Inline hose quick-disconnect simplifies refilling on the go
- Leak-proof Drylock bite valve with magnetic sternum hose clip
- Perforated 3D foam backpanel improves airflow and carrying comfort
- Breathable perforated shoulder harness enhances ventilation
- Removable webbing hipbelt for customizable support
- Top zippered quick-access pocket with integrated key clip
- Side zippered security pocket and stretch mesh bottle pocket
- Adjustable trekking pole attachment system
- Reflective attachment loops improve visibility in low light
- Custom ComfortGrip molded zipper pulls for easy handling
- PFAS-free DWR treated materials
Specifications
- Capacity: 18L
- Weight: 1.22 lbs
- Max Carry Weight: 20 lbs
- Dimensions: 19.3" H x 9.8" L x 7.5" W
- Main Access: Panel Loading
- Hydration Compatible: Yes
- Reservoir Included: Yes, 2L Hydro Reservoir
- Fits Torso: 16"–21"
- Fits Waist/Hips: 28"–48"
- External Pockets: 3
- Hipbelt: Removable Webbing Hipbelt Included
- Trekking Pole Attachments: Yes
- Closure Type: Zipper
- Pack Body: 210D / 420D High Density Nylon with PFAS-Free C0 DWR
- Pack Bottom: 420D High Density Nylon with PFAS-Free C0 DWR
- Lining: 40% Post-Consumer Recycled 135D Polyester with PFAS-Free C0 DWR
- Suspension: Perforated Multi-Density 3D Foam
- Warranty: Limited Lifetime
