The INA Belt Tensioner Base Plate Bearing - 7100012100 is a component used in automotive engines to maintain proper tension on the belt that drives various engine accessories such as the alternator, water pump, and power steering pump. This bearing is designed to be mounted onto the base plate of the belt tensioner assembly and helps to reduce friction and wear on the belt. It is made of high-quality materials and is designed to withstand the high temperatures and pressures of engine operation. This bearing is an essential part of the belt tensioner system and ensures smooth and efficient operation of the engine.