Based on your description of "metal sturgeon cans" and "rubber band seal," this most likely refers to "metal sturgeon cans" or "metal sturgeon sauce cans." This is a type of food packaged in a metal can with a rubber band seal.

　　What is a "metal sturgeon can"?

　　It's a food packaged in a metal can containing sturgeon or sturgeon sauce.

　　Appearance: Metal can body, usually with printed patterns.

　　Sealing: A rubber ring (or "rubber band," "sealing ring") is placed over the can opening, and then secured or pressed with a metal lid to achieve a tight seal.

　　Uses: Primarily used for storage and transportation, characterized by its excellent sealing and long-term food preservation.

　　What are the characteristics of this packaging?

　　Excellent sealing: The rubber ring fits tightly against the can opening, preventing air and moisture from entering and extending shelf life.

　　Easy to open: Usually, the contents can be easily removed simply by prying open the metal lid.

　　Wide range of uses: Besides sturgeon, this packaging is also commonly used for other sauces, jams, pet food, etc.