Fjallraven - Chest Strap for Kanken Backpacks SUPPORTIVE: Add the Chest Strap to your Kanken for extra stability and support. EASY: Attach or remove with the snap closures. FUNCTIONAL: The middle buckle doubles as a whistle. SAFE: The logo is reflective for extra visibility. COMPATIBLE: The Chest Strap fits Kanken and other packs with 25 mm webbing.