Bart's Own 'IMPERFECT' Premium Blue Dual Angle Sanding Sponges

High quality, firm, durable sanding sponges for wet or dry sanding, much more resistant than sandpaper and reusable after rinsing them out. 

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.