uSync Snapshots works with uSync to allow you to create moment in time changesets of your umbraco installations.
Normal usync will track changes you make to your umbraco installation and write any of those changes to disk, it also has the option to automatically take any changes that are on the disk and push them into umbraco. This is great when you are developing something, but some people find it a little scary, especially when they then start pushing things to live sites.
uSync.Snapshots, allows you to have more control over when uSync does this stuff.
If you install from the package below you will first need to install uSync - using nuget this all happens for you.