Buna Gaskets: Known as Nitrile, Buna, or Buna-N, this seal material is the standard gasket supplied by coupling manufacturers with the coupling. Buna is a good choice for water and petroleum applications. Relative to its cost, it provides resistance to various chemical compounds, but will start to see degradation of its flexibility in environments of high heat or consistent exposure to many chemicals. As a widely used cost efficient option, Buna seals can be a good choice, but care should be taken to ensure that the chemical being transferred is compatible with Nitrile such as, common lubricants, petroleum oils and water as well as avoiding avoiding mineral acids, and situations where the transfer system could encounter oxidation, or ozone exposure. 

PTFE Gaskets: Also called Teflon, these gaskets are some of the most specialized and costly in the industry. As a nontoxic fluorocarbon-based polymer the cost of this sealant comes with several material advantages. Excellent chemical resistance, excellent for slide bearings and liners, chemically inert in most applications, low friction coefficient, FDA approval (in many cases), provides electrical insulation, and soft texture allows for easy machining of specialized gaskets. Many specialized industries use the PTFE Gasket including pharmaceutical, cosmetic, complex automotive, and food & beverage. These sealants are used as components in a Teflon encapsulated rubber hose assembly, also known as a wetted rubber chemical hose assembly.