MOUNTAINTOP 50+5 Liter Internal Frame Backpack with Rain Cover 4 COMPRESSION STRAPS- For tying up your pack or hanging sleeping bag, tent, hammock, and other gears. Elastic bands on them can keep the extra strap from dangling all around the pack. EXPANDABLE COLLAR- A extension collar with two drawstrings on the top of the pack can?expand?it and increase the main compartment by 5 liters capacity. HYDRATION SYSTEM COMPATIBLE- Hydration access on a side of the pack with water bladder sleeve in the main compartment. ACCESSORIES-SBS zippers and YKK buckles. WARRANTY- Includes 90 days limited warranty.