Constant-level and drip-feed oilers ensure moving parts have a steady feed of lubrication as oil levels deplete over time due to displacement, misting, and evaporation. They mount permanently onto industrial machinery to lubricate gears, bearings, chains, and maintain oil levels in reservoirs such as gearboxes and bearing housings. Constant-level and drip feed oilers reduce maintenance needs by limiting frequent lubricant level checks and refilling of oil in equipment.