Genuine OEM Hyundai Crankshaft Belt Tensioner Assembly, part number 252512G110. This critical engine component maintains the correct tension on the serpentine or accessory drive belt, preventing slippage and ensuring efficient power transfer to accessories like the alternator, power steering pump, and A/C compressor. It is located on the engine's accessory drive system, typically near the crankshaft pulley. Choosing a genuine OEM tensioner assembly ensures precise spring tension, durable bearing quality, and correct alignment, which are essential for preventing belt noise, premature wear, and potential engine damage.