The Osprey Packs Siskin 8L Backpack offers just enough room for your water and a few absolute essentials when you're hitting the trails for a day of mountain biking or hiking. The included 2. 5L reservoir keeps you hydrated while the u-zip main compartment opens wide so you can stuff in a spare tube, repair tools, snacks, and an extra layer. The front of the pack has a LidLock attachment point for your standard size helmet, or, if you've got your full face helmet, the side compression straps expand so it fits comfortably. The Siskin's mesh covered backpanel and supportive shoulder straps make carrying the pack comfortable and easy so you can focus on the trail ahead.