Hmmm... a killer deal if you don't mind deficiencies in the filament strand. There's variations outside of +/- .05 (but barely so) OR it could be that the diameter is fine, but the filament broke during the extrusion process, so we wound a second filament onto the spool. Available colors run the rainbow. We'll send you a random spool and for $19.98, we think you're getting a GREAT deal. Hope you feel the same!