Product review (4 stars): Basically a good purchase
Received the order overnight with free shipping on my Prime account. Very tickling.

Almost returned it because our range hood's duct vent is horizontal while the product calls for a verticle duct. Cutting a rectangular opening in the back was not an option.

Then, I was enlightened by a post from a housewife on a Chinese website which provided a step-by-step solution with excellent photos.

At a Home Depot store, I found the 6" flexible duct difficult to bend within the cabinet's 21-inch height. So, I switched to a 6" to 4" reducer and two 4" 45 elbows. A wood piece was used to strengthen the support. The enclosed hardware for support was not needed.

The installation took 4 hrs of our friend who is a master handyman. Paid $10 to rent for 4 hrs a box of hole saws from the nearby hardware store. Needed to cut one 6" and two 4" holes. (Will add a photo soon.)

The package came with no info of manufacturer but with reseller's two addresses in Pomona, CA. In addition, in view of the special English in the User Manual, it ought not be surprised if it was made in a foreign country.

The instructions about setting clock were incorrect. The setting button should be the one that toggles the lights on/off.

A Radio Shack Sound Level Meter (Cat. No. 33-2055) was used to measure the noise levels at high speed:  87 dB at 6" from a fan, 72 dB on the eye level at a normal standing position when cooking.

The weak LED lights are easily compensated with two inexpensive magnetic LED lights.

The actual effectiveness of catching oil and grease needs to be tested and confirmed. Many Chinese users complained of the misleading, high CFM. They said that other brands with lower CFMs and better positioning of the fans are more effective in capturing oil and grease from the four stove heads.

The product is identical to Golden Vantage`s same model number, which also sells for $300 but adds $33 for shipping.

The Golden Vantage 30" model number R01-75 has these differences:
8" duct opening;
Has remote control and gas sensor;
Cosmetic difference of the baffle filter and the control panel; and
Costs $400 plus shipping.