This is a fan adapter for replacing a 92mm fan with a 120mm fan, which will give you better airflow and lower noise. This adapter is perfect for your noisy stock or budget 92mm cooler.
Make sure you have enough space as it can collide with tall ram sticks. This 3D model is printed in two parts, the 120mm part has a ring and the 92mm part has a cone, both of which should be orientated upwards.