I think its a plastic.
Give it to them inside a water bottle. Hang the bottle on the side of the cage with a metal hook that you should be able to purchase with the water bottle.
the metal cap will expand , and it will be easier to remove the cap from the bottle
Yes, you can take a metal water bottle on a plane, but it must be empty when you go through security. You can refill it at a water station or after passing through security. Make sure to check with your airline for any specific requirements.
The heat causes the metal in the cap to expand making it looser around the bottle
A water bottle is a container that is used to hold water, liquids or other beverages for consumption. The use of a water bottle allows an individual to transport and carry a beverage from one place to another. A water bottle is usually made of plastic, glass, or metal.
Heating the metal causes it to expand, which increases the size of the metal cap. As the metal expands, it creates more space between the cap and the threads of the bottle, making it easier to twist off.
The heat expands the metal.
Usually an army water bottle with metal cup, a fire steel and knife.
I'm not sure that you can, unless you are a blacksmith or metalist. MB advice
In general, water in a metal can will freeze quicker than in a plastic bottle. This is because metal is a better conductor of heat than plastic, allowing the heat to escape more rapidly from the water in the metal can and causing it to freeze faster.
If you are interested in buying a water bottle for running, I highly reccommend you looking at your local Sports Chek. They have many to choose from, from plastic ones to metal ones, as well as how much water they hold.