Great deal! But the mouse is by no means heavy, at 89g. Completely innocuous but yet super easy to remove. I wear a shoe size 6. Holding the bar on the end with cupped hands caused hand cramping. Imagine 150 people in a huge room of long tables and you get the idea. There was no size chart and there were only 2 sizes offered: small/medium or large/extra large. It was pretty easy to install, and I find it to be comfortable on my ears, though right now I am finding my head phones to sound a little bit low. They don?t work with cold weather. I want to headline this review first with a buyer beware; if you are thinking of buying this or already have bought it, make sure your mouse does not have creaky clicks.