Does the Job.
The plastic is pretty thick. Therefore I haven't had any leaks or broken bags so far, but mind you I only use it casually. I like how there isn't much plastic smell, when opening the bag. With the double zipper, there is good and bad about it. Yes it does securely store the milk and leak proof, however after the bag goes in the freezer, the stiff closure makes the bag hard to open. After all it does the job, but just abit pricey.