Lantern rings, also called seal cages or flush rings, are grooved metal spacers positioned within packing stacks to introduce lubricating or cooling fluids into the stuffing box, improving packing lubrication, reducing friction and heat generation, flushing away abrasive particles that penetrate the outer packing rings, and extending packing service life in severe applicaLantern rings... https://globalsealstech.com/product-category/oil-gas-seals/high-pressure-water-pump-seals/