What are these called?

Hi i need to know what these are and what they do. can someone help me please
https://i.gyazo.com/d20977ae6aaabc74117d488172f100cd.png

Crow's foot line sockets-- used to remove, install, tighten line nuts. with a 3/8 socket wrench drive adapter--- like anything that has a nut over a rigid pipe. An example would be a transmission cooler line that is threaded into a radiator. In most cases, most techs would simply use a straight wrench. but some would argue that these crow's feet get a better grip on the nut. You use a 3/8 drive extension from your socket wrench to drive this crow's foot.