This Viton o-ring kit is packaged in a clear, plastic box with a re-sealable lid that lets you see the o-rings inside

The viton class of elastomers is a family comprised of linear co-polymer of vinylidine flouride and hexafluoropropylene. Fluorine content is between 66 to 70%. Generally black in color, and with generally good temperature and chemical resistance.

It opens to 30 compartments, each clearly marked with the rubber type, o-ring size, and quantity included. The cardboard insert indicates the codes for each size, so you can easily re-order the o-rings individually as they are depleted. The quantity of each o-ring varies by size and compartment, but the kit contains 500 total o-rings.