What is the thing used with guitar players that goes on their finger that acts as a ln ajustable capo?

The region of the united states where beef and hog production is prevalent is the midwestthere are 12 states in this area including  illinois,  indiana,  iowa,  kansas,  michigan,  minnesota,  missouri,nebraska,  north dakota,  ohio,  south dakota, and  wisconsin. all of these states are known for their meat and such products. 

Prepared to discuss your findings with your teacher or fellow students