I don't know why this fan was discontinued. The inlet and outlet breather hoses cannot be securely clamped without further modification to the fan housing. Both the inlet and outlet flanges are narrowed so that when the clamp is tightened, the hose and clamp slide off the flange. In addition, the body is covered with very slippery paint, which makes assembly even more impossible. Mounting the fan may be challenging for some as the fan housing completely covers the holes in the mounting bracket. This should not prevent a successful installation. Just something to consider. The noise level is what I would expect from a fan of this size and airflow. The whole assembly makes a very solid impression. I haven't decided to return the fan yet. There are many tools in my shop to solve the above problems, but if you want to buy a fan, hang it and use it, you can try other products. Installing this fan requires a significant amount of effort.