Bart's Own XL Single Angle Sponge with Imperfections

Extra large sanding sponges for wet or dry sanding, much more resistant than sandpaper, and covering more area than a regular sanding sponge.

What is the difference between a regular and an Imperfect sponge? 
An Imperfect sponge are the offcuts, the ones that are a bit rougher around the edge of cuts or slightly crooked. Minor traits that make them a bit more 'imperfect' than the regular cut sponges.