Honda 91303HA0004

The Honda 91303-HA0-004 (91303HA0004) is a genuine OEM O-ring seal (11 × 1.9 mm).

It is a small rubber sealing ring used in Honda engines and systems such as oil passages, covers, or hydraulic/fluid fittings, depending on the model. Its job is to provide a tight, leak-free seal under pressure, preventing oil or fluid leaks and helping maintain proper system integrity.