That is 3" wide in my scale and a really nice size. Wide enough to give a good stretch but not too wide to make it difficult or painful to take and keep in. I'd love to have one but I'm a bit past 3" (75mm) these days.
Thanks for the comment. It's just like you say. The video is from about two years ago, when what I wanted was to expand to get to bigger toys. This is an intermediate step (75mm) that I still use today for progressive dilation.