BOLU manufactures Bi-metal Liners and Ceramic Zirconia Liners. BOLU also supplies genuine rubber and urethane liner seals. All our liner products are exchangeable with OEM products and meet or exceed API-7K standards. Bi-metal Liners High strength alloy steel outer hull High Chrome alloy inner sleeve honed to mirror finishes HP design to prevent inner sleeve slippage Exchangeable with OEM products Meet or exceed API-7K standards