What am I?

I am a king but also a measuring device. What am I?

related riddles

I can be red, blue, purple, and green. No one can reach me, not even the queen. What am I?

*Forward* *backwards* is what I do all day. I come in all different shapes and sizes. I can be scary, and I can calm you down. What am I?

I have one eye but it doesn't see, what am I?