Drinking
热水 (hot water) is a deep-rooted Chinese health habit, so the
保温瓶 — at home, in the office, on long-distance trains — is more than a convenience. The big bedside
暖水瓶 (covered in cane or tin) was an iconic 1980s wedding gift; today's compact stainless-steel
保温杯 /
保温瓶 (Mainichi, Thermos, Stanley) is its descendant.