Aonijie C933S Hydration Vest is a good running vest for any distance between 12-30km running, capable of carrying 2-3L of water, some fuel and supplies. 

Features:

-Made of ultralight elastic nylon cloth, polyester, breathable mesh back and shoulder strap.

-Ergonomic design, Vest-shaped bag coming with adjustable waist strap and high elastic chest strap.

-Weight 145g, Capacity 5L. The maximum loading weight is 10.2kg.

-Designed with multiple exterior pockets, large enough to hold all your necessities


Specification:

Brand: AONIJIE                                                
Model:C933S
Material:75% nylon,25% spandex                    
Lining: 100% polyester

Net Weight:145g                                              
Capacity:5L
Water Supply:1.5-2L water bladder(not included)  

Package Content:
1x C933S Hydration Backpack

What kind of water bladder should you get to match the vest? 

Normally any 1-2L bladder should fit this vest. To be on the safe side, please also double check the dimension of the vest & the bladder you have/ are going to buy.