Pro Manila rope is designed for applications where you want the look of classic manila with out some of drawbacks of regular manila.
Pro Manila will not rot or shrink when it gets wet like manila will. This product is actually made using a unique processing method that makes it different from other polypropylene ropes. In order to get the "manila rope look" we start with a flat polypropylene film and then use that to make the individual rope strands. The result is a rope that replicates the look and feel of manila.
Here is a close up of the fibers for this rope, you can see how they have the various widths and texture to get that classic manila feel.
If your rope use requires a rope that will be around chemicals, lots of water, or you just don't want a rope that shrinks when it gets wet, this is a great product to consider.