The zinc bottle is about 90 years old. It is 11 in. long X 8 in wide and in very good condition.
A bit of background. Containers for warmth in bed were used as early as the 16th century. The advantage of using hot water was that the container could remain in the bed with the sleeper, although they were often wrapped in soft cloth to avoid buring the sleeper.
For a comparable price ($23.00 + postage), see https://www.ebay.com/itm/Old-Hot-Water-Bottle-Zinc-Bed-Warmer-Antique-/254135961493