Features:
HIGH VISIBILITY TO BE SAFE: Reflective material which is quite luminous at any light ray at night ensures safe running or cycling at night.
PREMIUM MATERIAL: Made of firm, breathable, light and durable material.
MULTI-FUNCTIONAL POCKETS: Enough pockets and pouches that can store items like cell phone, keys, thin raincoat, 500ml soft water bottle, 1.5L hydration bladder and other items for outdoor activities.
LIGHTWEIGHT, ADJUSTABLE & VERSATILE: Fully adjustable and breathable design allows a full range of motion for all runners, joggers, bikers, kids and adults. Perfect for any outdoor activities such as running, cycling, walking, mountaineering and so on. 
COMFORTABLE FIT WITH SPECIAL DESIGN: This backpack gives a comfortable fit over sports gear and accommodates the majority of body sizes. Two sizes available: S/M, L/XL.

Specifications:
Type: Running Hydration Backpack  
Brand: AONIJIE
Model: E906#
Material: 100% Chinlon
Color: Black
Size: S/M (For chest circumference 80-97cm) / L/XL(For chest circumference 97-109cm) (Optional)
Capacity: 5L
Gender: Unisex
Size: 41 * 39cm 

Package includes: 

CJBHNSNS08102-Bag S M 2pcs 500ML BTL : 1*black bag S/M+2*500ml bottles

CJBHNSNS08102-Bag S M 2pcs 600ML BTL : 1*black bag S/M+2*600ml bottles 

CJBHNSNS08102-Bag S M 2pcs 500ml BTL 2L: 1*black bag S/M+2*500ml bottles+1*2L water pouch

CJBHNSNS08102-Bag L XL 2pcs 500ml BTL 2L: 1*black bag L/XL+2*500ml bottles+1*2L water pouch 

CJBHNSNS08102-Bag L XL 2pcs 600ml BTL 2L: 1*black bag L/XL+2*600ml bottles+1*2L water pouch