Lockdown screw seals, often HNBR with stainless caps, seal adjustment screws in wellheads. They outperform traditional metal seals in geothermal or corrosive settings. Packing designs resist pressure and temperature extremes while preventing leaks around threaded penetrations. API-compliant compounds ensure long service in sour conditions https://globalsealstech.com/product-category/oil-gas-seals/api-6a-wellhead-equipment-seals/