This is a “Top Off”. Today we call it a can opener. It was made in Burlington, Vt by Edlund Co.
This belonged to my great grandparents. They were the first people on their family to be born in America. Their family came from Eastern Europe. My grandpa grew up with this “top off” in his home. We still use it today. I find it very useful. 

– Lior Gross-Prinz

Relationship:  Great-grandchild of im/migrant or more Great-grandchild of im/migrant or more