CamelBak Boy's Mini Mule 50 oz Hydration Pack Nylon Pack features include: bike tool organizer pocket, reflectivity, safety flasher loop, sternum strap whistle Wicking mesh back panel and mesh shoulder straps are cool and comfortable; straps are adjustable so the pack still fits as kids grow Big Bite valve is easy to use, just bite and sip HydroGuard Antimicrobial Technology eliminates up to 99,99% of common bacteria and fungus on reservoir and tube surfaces Reflective highlights increase visibility in low light