Filament Spool Gauge

I was tired of guessing at how much filament remains on a spool that doesn't have a gauge built into its side. I designed this gauge so that I could at least have a better guess than "Not Empty" or "Almost Full".

To Use... Simply place this gauge on the top of the remaining filament against the inside spool wall and read the % or actual footage remaining directly through the center window. (See Photo) No moving parts and the math is all done for you.

It was designed for Hatchbox 1 Kg Spools but will work on any spool with a 200mm outside diameter and a 80mm diameter core which is pretty much the industry standard.