Modifier ZirJars are designed for coloring liquid you do not go through very fast and/or that are brushed on. These ZirJars are insulated to reduce temperature fluctuation which can lead to shorter shelf life and evaporation. The ZirJar protects its continence from natural and artificial UV light that can brake down the chemical bonds of the coloring liquid altering the final zirconia shade. All ZirJars feature flip top lids that make it fast and easy to dip or brush your full contour and substructure zirconia. Not having to remove the lid eliminates the chance of putting the wrong shade lid on the coloring jars. Also, condensation and splash leaves the inside of the lids covered in coloring liquid that can drip onto your work place when removing and setting down. That can lead to cross contamination shading. Modifier ZirJars are a great investment in your zirconia coloring system.