What's this?

As my profile says, I am fairly new to restoring vehicles, I still have a lot of things to learn. As I am taking my truck apart I am finding things that I have no clue what they are. I found this and know it is something to do with the battery, I am not too sure what it is actually called, if anyone could help it would be great.

 

Looks like a starter solenoid to me.

 

Starter solenoid.......Ford right?

 

I agree, looks like a solenoid, probably starter due to the "beefiness"

 

Thats it, thanks. I was looking right at it before in a catalog but didn't actually see it

 

Corroded FoMoCo solenoid. Get a new one.

 

When you buy a new one get a Standard Brand with a button on top so you can start your car with the hood up MAKE SURE! It's outta gear and the keys off!!

 

Or just use a screwdriver between the posts.