Ultimate Direction Fastpack 20 Vest Backpack

• 23.4 litre capacity: Provides space for additional clothing, food, mandatory kit and multi-day equipment while retaining vest-style access at the front.
• Front hydration pockets: Two upper pockets with bungee compression accept 500ml Body Bottle 500 and Body Bottle 500 S soft flasks. Soft flasks are not included.
• Accessible front storage: Two lower open-top pockets, four further stretch-mesh open-top pockets and two water-resistant zipped pockets provide storage for food, phone, maps, headlamp, glasses and other smaller items.
• Full-side zip access: Opens deep into the main compartment so equipment can be reached without unpacking everything through the top.
• Roll-top closure: Expands or compresses around changing loads and secures the top of the main compartment.
• Infiknit and FastFlow back panel: Seamless harness construction combines with a breathable back-panel system to improve airflow and moisture management.
• Side storage: Two large side pockets provide accessible space for larger water bottles, clothing or other equipment.
• External stretch storage: Large rear stretch-mesh storage keeps additional clothing and frequently needed equipment outside the main compartment.
• 3 litre reservoir compatible: Accommodates a reservoir up to 3 litres. Reservoir not included.
• Sliding sternum adjustment: Rail-mounted sternum straps allow quick adjustment across the chest.
• Removable T-hook waistbelt: Height-adjustable belt provides additional support with heavier loads and can be removed when unnecessary.
• Side fit adjustment: Allows the pack to be adjusted around the runner and changing loads.
• Trekking-pole carry: Dedicated attachment points allow folding poles to be secured to the pack.
• Internal secure pocket: Provides separate storage for keys and other valuables.
• Daisy chains: External attachment points provide additional options for securing equipment.
• Ice-axe loops: Provide external attachment for an ice axe when required.
• Safety whistle: Integrated into the front harness.
• Reflective detailing: Adds visibility in low light.

The Fastpack 20 uses a unisex vest-style harness with sliding sternum adjustment, side adjustment and a removable height-adjustable waistbelt. Measure around the bottom ribs while wearing the clothing you expect to use with the pack.

The size ranges overlap. A fully loaded pack will fit more closely than an empty one, so intended clothing and typical load should be considered when choosing a size.

For an overview of Ultimate Direction running vests and Fastpacks, see our Ultimate Direction pack guide.

If you are deciding how much carrying capacity you need, see our Running Backpacks, Race Vests & Hydration Packs Guide.

If you are unsure about sizing, Fastpack fit or whether 23.4 litres provides enough capacity for your intended ultra, multi-day run or fastpacking setup, get in touch for straightforward advice.