Flexible Shipping - Shipping method - Advanced Options
Visibility - check to show this shipping method only for logged in users.
Default - check to make this shipping method default during checkout.
FS Debug Mode - tick to turn on the FS Debug Mode for this particular shipping method. Especially useful for troubleshooting. You can learn more about the debug mode from this article.
DIM Factor - enter the DIM Factor value used by the carrier you ship your products with to calculate the dimensional weight.
The dimensional weight, known also as DIM weight or volumetric weight in turn, reflects package density, which is the amount of space a package occupies in relation to its actual weight. It is calculated according to the following formula:
(Lenght x Width x Height) / DIM Factor = Dimensional weight
So the package volume obtained by multiplying its lenght by width and height is then divided by the DIM Factor used by the carrier giving the Dimensional weight as a result.