The purpose of all o-rings and o-ring kits is to provide a good seal for valves and flanges, as well as faucets. All of our o-ring offerings conform to AS568 standards for sizes and tolerances. From there, they differ in terms of their composition relative to their application. As a few examples: Viton® o-rings are best for providing a seal where chemical resistance is important. Buna-N o-rings are best for providing a seal where oil resistance is key, and silicone for heat resistance, and EPDM for steam resistance, and PTFE for temperature resistance, Polyurethane for toughness and resistance to tears, and so on. Zoro supplies o-ring assortment kits in a variety of compositions and sizes, as well as kits that are sized metrically. And if you’re looking for o-ring splicing kits, lubricants or installation tools, be sure to check out our o-ring accessories.