Donaldson, founded in 1915, makes filtration products and systems that protect equipment and processes across industries including construction, mining, agriculture, commercial transport, industrial manufacturing, aerospace and defense, and life sciences. The core business is organized into three segments: Mobile Solutions (~62% of revenue), Industrial Solutions (~30%), and Life Sciences (~8%). Mobile Solutions sells air, fuel, lube, hydraulic, and emissions filtration for off-road and on-road equipment, and is anchored by a large aftermarket replacement filter business that accounts for roughly 75-80% of segment sales. Industrial Solutions sells dust collectors, compressed air and gas purification systems, hydraulic filtration, power generation air inlet systems, and aerospace and defense filtration. Life Sciences covers disk drive filtration, food and beverage filtration, and bioprocessing equipment and consumables — the latter still in early commercialization. Donaldson's business model follows a "razor and blades" dynamic: Donaldson wins a spot on new OEM equipment at the factory, then generates recurring, higher-margin aftermarket revenue from replacement filters throughout the machine's life. This recurring aftermarket stream insulates earnings from weakness in new equipment production cycles. Margins are primarily driven by mix — aftermarket parts carry materially higher margins than OEM first-fit sales. Donaldson's growth strategy focuses on expanding its Life Sciences bioprocessing business through acquisitions, deepening industrial customer relationships through connected filtration technology, and acquiring regional industrial service businesses.