A pair of pliers is a tool that you can use to twist metal or to grip a tiny object. Jewelry makers often use small, narrow pliers to bend thin pieces of wire.
There are many different types of pliers that do various jobs, from large, wrench-like pliers that plumbers use on pipes to tiny "needle-nose pliers" that electricians can fit into narrow spaces and grip small wires. Why pliers always come in "pairs" like jeans, eyeglasses, and scissors is a bit of a mystery. The word stems from the verb ply, "work with" or "use."