eSUN PLA % LEFT Gauge

I noticed lots of filament spools lacked percent remaining indicators. I happen to use eSUN PLA a lot and decided to create an easy to use gauge for measuring approximately how much filament remains on a spool. To use the gauge, just slide down along the inside face of the spool with the markings facing outward until the gauge stops on top of the remaining filament. The marks nearest to the top of the spool indicate the approximate remaining percentage of filament. A reading of 60, for instance, indicates that there is 60% or 600 grams of filament remaining on the spool. Please note that this gauge is based off a standard 1 kilogram plastic spool of eSUN PLA as shown in the provided images. If you would like to verify that this gauge has been calibrated for your spool, you can do so by comparing the following three measurements:Outer diameter of the spool: 20 cmDistance from the top of the spool to the top of the filament when at full capacity: 1.36 cmDistance from the top of the spool