It contains plenty of features that will greatly help you improve your unwrapping workflow.
Main Features Features

Multi Stitch. Stitch Multiple Shells at once
Custom Packing algorithm and tools
Tool for matching the Shells Width and Height
Easy Grid Spacing
Render UV Tiles (UDIM)
Cycle Checker map
PolyUnwrapper Toolbar now keeps on top of the Unwrap Editor
Render Open Edges

Home Page – http://www.polytools3d.com/polyunwrapper/