Clip-on Loupes Ultra-light Binocular 3.0 X 360-460mm Working Distance Dental Medical Surgical Use by Dental Power

These are heavier than described and since they clip onto glasses, they drag the glasses down. There is a knob to adjust the loupes to fit the distance between both eyes. But it doesn't remain steady. I don't find this product satisfactory at all. I'm requesting a return/refund.