The Aonijie soft running flasks are enticing that is for sure. The low price and the Salomon look really draw runners to them, like Sirens in Greek mythology. I will be honest, I was drawn to them less than a year ago. So I purchased two of the Aonijie 500ml flasks for an upcoming trail run, the 2018 Rebecca Mountain 50 Mile Trail Race (link to my post race report).

For the race, I ended up using the two soft flasks that came with the Ultra Tri running vest I ordered off AliExpress. They worked great for the race and are still my go to running flasks, along with the running vest. I say all of this because I technically did not try the Aonijie flasks until recently, months after I purchased them. Here’s the link to my Ultra-Tri vest review post, here.

I’ll cut to the chase with this review. I don’t need to spend a lot of time explaining why soft flasks are great. But, in case you did not know… soft flasks are perfect for short and long runs, walks with dogs, hiking and bikepacking trips. Their lightweight design, flexible construction and vast functionality are the key reasons why individuals purchase them.

My Review:

For the Aonijie flasks there are two reasons why I cannot recommend these to anyone. These are deal breakers for me and should be for you too. The first reason is the cap leaks under any kind of pressure. The second reason is the poor water flow through the bite valve. Below are my explanations of my experiences and pictures providing you proof.

1. The Cap Leaks

The problem with the cap is it does not have a rubber gasket to create a tight seal on top of the threads. I even reached out to the official Aonijie store via AliExpress’ messaging function in their app to ask if they sell them without rubber gaskets. They confirmed they do not sell the flasks with any type of rubber gasket (see the second image for our conversation).

Even if you tightly thread the cap on it still leaks because it is plastic on plastic. The plastic I guess is uneven in spots so the water pushes up and through the threads and then down the flask. You can see how it fills the threads and slowly drips out in the picture below.

I did find it leaks less if you leave a little air in it because it creates a small barrier between the top of the flask and the cap. If do you suck all the air out to prevent the sloshing it tends to leak more because it seems to create a vacuum, pulling the water out during the run. That vacuum effect is exacerbated when the flask gets compressed by your running vest and your chest when running.

The picture below is the conversation that I had with them through the AliExpress app. I was hoping they sent me two flasks without rubber gaskets by mistake, but as you can see that is not the case.

The picture below contains the Aonijie cap on the left and the Ultra-Tri on the right. You can see the clear rubber gasket in the Ultra-Tri cap and nothing in the Aonijie’s.

2. Poor Waterflow

The low flow rate is what I dislike the most with the Aonijie flasks. It takes too much work to get water out of the flask while running. I end up more out of breath trying to squeeze and suck the water out of the flasks than I do after a short sprint. The bite valve is the issue because it does not seem to open on both sides like it does with the Ultra-Tri flasks. You can get better flow if you bite back the edge of the nipple, but takes too much concentration for me to do it each time.

Below is a picture showing the difference between the two. You can see the dual streams coming out of the Ultra-Tri and just the solo stream from the Aonijie’s. And, below that picture is an illustration of what I think is happening.

More Pictures:

Amazon.com

AliExpress.com

REI.com

Backcountry.com

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-theBidon