 Sometimes we need to zip or unzip a collection. What does it mean? So here I have a collection of paired reads. So this collection effectively has two levels, right? This is collection. This is the first level, individual samples, and once we drill down we see forward and reverse reads for each sample. So let's unzip this collection. Unzipping really does the following. So you take a collection, you run unzipping tool, it produces two collections. In this case with only forward and reverse reads. Let's do that. So I'm going to go to collection operations, select unzip collection tool choose the collection I want to unzip, I really only have one and run it. And this will generate two collections. Forward collection with only one level. We drill down two reads immediately and reverse collection also with one level. So what you can also do is you can zip collection back in. So what does zipping do? Zipping takes in this case two collections and creates a single paired collection out of them. Let's use this tool. In your collection operations again use zip collection, select the forward collection first, reverse collection second and run execute. And here it is and it has two levels.