Penray’s extended service coolant elements, Nos. NF3088 and NF3999, release Supplemental Coolant Additives (SCA) only when the truck’s cooling system needs them. The elements can sense the corrosivity of the coolant and add the SCA when needed for continuous protection. The NF3088 lasts 150,000 miles and the NF3999 50,000 miles. The NF3088 otherwise times out at 15 months or 3,000 driving hours. Both are compatible with all types of antifreeze and contain a filter cartridge, gasket and maintenance stickers.