To download in different formats e.g. svg and png
If in Sketch, you mark an asset as exportable as png and as svg, we'll give you the option to download both of these formats in the Handoff tool.
To download different sizes
You can export the same element in multiple sizes e.g. 1x, 2x etc. and we will have all of those available to download individually and as a ZIP. This is great, as it allows you to ensure icons and images will look crisp across different screens and devices, and developers have easy access to all the assets.