This tetsubin was made by the famous Long Wen Tang Company in the early 1900's. The workmanship is good and there is some low-medium rusting inside. There is a thick layer of mineral buildup from years of boiling good quality water inside. This has started to flake in places, but still covers most of the inside.
The tetsubin is solidly made (2.5kg) and holds the heat well.
The water quality is good. Thick and sweet.