Grease injection seals (flow tubes) are ceramic or tungsten-coated stainless tubes that work with high-viscosity grease to form a dynamic hydraulic seal around moving wireline. Ultra-smooth internal finishes below 0.2 µm Ra and precise concentricity ensure minimal grease consumption and maximum pressure containment in HP/HT wells. https://globalsealstech.com/product-category/oil-gas-seals/oil-free-lubricated-pump-seals/