mediumwhat am-i
Illustration for riddle: When I am filled I can point the way, 
When I am empty Nothing moves me, 
I have two skins 
One with
Can you figure out this riddle?

When I am filled I can point the way, When I am empty Nothing moves me, I have two skins One without and one within. What am I?

Common Wrong Answers

A compass

While a compass does point the way when it is filled with a magnetic needle, it does not have 'two skins' as mentioned in the riddle.

A bottle

A bottle can point the way when filled with a liquid, but it does not have two skins and the concept of being empty does not relate to movement.

A map

A map can point the way when it is 'filled' with information, but it does not have physical skins, and being empty does not stop it from providing directions.