Very nice product, exactly what I was looking for. I use this for loose leaf tea so the filter keeps the leaves away from my mouth. The glass feels sturdy and I expect it will hold up over time. I had no problems pouring boiling water into it. Please note that 400mL is the capacity to the rim of the glass. If you fill it only up to the filter, it's ~340mL. This is a good amount for me, but I just thought people should be aware of that.
I LOVE it. Very nice.