I'm a tool that comes in different sizes,
I help you tighten and loosen things with ease.
Some have a ratchet, others just a plain head,
But all have a handle that fits in your hand.

I can be used on nuts and bolts, big or small,
Whether you're fixing a car or hanging a picture on the wall.
Some are shiny and new, others rusty and old,
But no matter what, I'm always there to lend a hand to hold.

What am I? A wrench!