Stay hydrated and comfortable on your trail runs, marathons, and hikes with this sport hydration vest running backpack featuring a polyester mesh fabric for optimal air circulation. The backpack has multiple storage pockets to secure your essentials, adjustable waist and chest straps for a customizable fit, and reflective trim for visibility in low light. It comes with both 15oz and 50oz water bladders, ensuring you can easily stay hydrated on the go. Available in black, grey, and blue, this backpack is suitable for various outdoor activities and is designed to meet both your functional and style needs.