I found a thick one.

The one I used before was thin, so it felt like it was harsh on my skin.

I was planning to buy one if I saw a thick one, and I found it at Daiso.

It is very light and easy to hold.

There are options with deep curves and soft curves, so they fit well anywhere.

It's really the best for loosening up calf muscles, too.

I use multiple of them in rotation.