United Scientific OBSET3 Optical Bench Set - Complete Physics Lab Equipment for Light & Lens Experiments | Perfect for Classroom, Homeschool & Science Labs

I hope I could give a negative five star rating. Upon arrival, the only thing in good shape is the bench.1) Upon first use, the liiuminator did not light up. I took it apart and found the light bulb is blown. Both inside and outside of the illuminator lens is dirty and blurry.2) All lenses and mirror are covered with dirt, glue and scratches. I tried to clean one up with a camera lens cloth. The dirt and glue can be cleaned up, but scratches are still there. They don't seem usable at all.3) The lenses do not have any marks to indicate focus length etc, and the glass quality is not even as good as window glass. Optical lens is supposed to be packaged carefully, but in this shipment, the lens comes in plastic bags, which tells these lenses were handled as junky.If you want something useful, don't buy it. I would recommend avoid this brand based on my experience.