I have now tested Libre Tea's glass 'n poly (large, 420 ml) product. I enjoyed the brewing process and the beverage tasted very good. The only thing is that it could take time to get used to sip from this kind of container / hollow-ware, compared with a regular tea mug. I have to test Libre Tea mug sometime in the future.
Libre Tea glass (3 parts).
Pour loose tea leaves into the filter.
Turn the container upside down and let it brew.
After a couple of minutes, you have a fresh glass of tea! (Steep time: circa 3 minutes for Assam black tea.)