HK Series Industrial Interchange Series B Dust Plug, -12 Coupling

Beyond the standard Buna-N, you've got four other seal materials to choose from: PTFE, Neoprene, FKM, and Kalrez. For aggressive fluid environments, FKM tends to hold up well and is rated for temperatures up to 400°F, which gives you a solid buffer in demanding conditions. EPDM is another option if your temperature range dips low, as it handles down to -65°F. The right pick really comes down to what specific fluids you're running, but those options give you good coverage across a wide range of chemical and thermal conditions.