Adjustable shoulder strap,chest strap and waist strap to fit your need.With whistle design on the chest strap.Ergonomic design on the back for maximum breathability and comfort.Reflective strips for safe riding at night.Rain cover included.Suitable for outdoor activities like cycling,rock-climbing and hiking,etc.Showing your brand wherever you go! Made from nylon material, measuring 11.4*16 inch, this custom nylon hydration sports backpack with thermal water bladder. Usage Scenarios: Office supplies, school stationery, corporate promotions, trade show giveaways. Customization available: Print your logo or customize packaging and color schemes. Product Highlights: Portable, durable, practical for daily use.