This is a measuring instrument (color RED) used to measure the current in a circuit.

https://www.amazon.com/gp/product/B07Y89632T/ref=ox_sc_act_title_1?smid=A18RFE6ZVD9PX6&th=1&pldnSite=1

From Fred Kral in our Science Department: In Physics class, when we study electronic circuits, we quickly run out of handheld multimeters used to measure voltage and electric current. These small 5-digit meters would improve future labs by increasing the number of devices and by providing much higher precision.