Low density weaves(not tightly woven), bad weave patterns(imperfections) thin weave, lots of epoxy to give the smooth look, much heavier than a quality CF, usually not vacuumed to pull as much resin out as possible (makes it lighter and if proper CF is used stronger).
Just a few things cheaper CF is about. Not o mention you almost always need to trim areas or drill out holes since they are off a little or just in the wrong spot.[smirk]