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Gregory Inertia 18 H2O Backpack

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Meet the Inertia 18 H2O daypack, where comfort and convenience collide. An included 3D Hydro reservoir and perforated 3D foam backpanel provide a complete hiking hydration system ready for all-day adventures.


3D Hydro Reservoir Included
  • Included in a dedicated zippered compartment is a 2 liter 3D Hydro reservoir with patented 3D molded design that works like a reservoir and dries like a water bottle.
Perforated 3D Foam Backpanel
  • Multi-layer foam construction with 3D Foam on the surface layer provides space for airflow even with the pack on your back.
Multi-Functional Organization
  • Exterior accessed, secured zippered pocketing and a dedicated hydration compartment that can double as a smaller laptop or tablet sleeve, allow these packs to transition from trail to transit with ease.
  • Includes 3D Hydro quick-drying, soft-molded reservoir (2 Liter) with integrated handle and drying hanger
  • Dedicated 3/4 zippered hydration sleeve with SpeedClip hydration hanger for a one-handed, snap-and-go connection
  • Inline hose quick-disconnect coupling for easy refills without having to un-thread the hose from the shoulder harness
  • Perforated shoulder harness with magnetic sternum buckle and hose clip for the Drylock bite valve
  • 3D foam backpanel with supportive multi-density foam
  • Removable webbing hipbelt
  • Top zippered quick access pocket with key clip
  • Side zippered pocket for on trail, secure access and side mesh bottle pocket
  • Reflective attachment loops and adjustable trekking pole attachment system
  • Custom ComfortGrip molded zipper pulls


Item# 1413380413
Ideal Fit For Men
Activity Day Hiking
Suspension Technology MOMENTUM
Compartment Access Panel
Closure Type Zipper
Number of External Pockets 3
Hydration Compatible Yes
Hipbelt Included Yes
Trekking Pole Attachment Yes
Fits Torso 14" - 19" / 35.6 - 48.3 cm
Fits Hips / Waist 27" - 45" / 68.5 - 114.3 cm
Weight 1.22 lbs. / 553 g
Volume 18 L / 1098 cu in.
Max Carry Weight 20 lbs. / 9.1 kg
Packed Dimensions 19.3" x 9.8" x 7.5" / 49 x 25 x 19 cm
External Material 100% Nylon
Pack Body 210D High Density Nylon & 420D High Density Nylon with PFC-Free DWR
Pack Bottom 420D High Density Nylon with PFC-Free DWR
Lining 40% Post-consumer Recycled 135D Polyester with PFC-Free DWR
Suspension Perforated Multi Density Foam & 3D Multi-Density Foam