bi-metallic cylinder liner payment:L/C or T/T delivery :10-15 day packing :general packing API Premium liners: DL premium liners combine the strength of a forged steel outer shell with the abrasion and corrosion reisistance of a high chromium iron inner sleeve. The liners feature a centrifugally cast high chrome iron sleeve which is machined and heat treated to a minmum uniform bore hardness of HRC62. The inner surface of the liners with a mirror-like smooth finish and the inner holes’ dimension tolerance is strictly controlled to ensure a long using life of more than 800 hours. DL premium liners are made for superior performance under tough corrosive and abrasive conditions.