what is that window tank on old cars?

sorry for the general dumb question, anyone know what that little extra tank on the passenger side window of the old school lowriders? whats it called, what was it for, all that kind of stuff... was it a factory thing, what kind of cars it came on etc... anything would be helpful!

I believe it is a type of a/c

ITS CALLED A SWAMP COOLER.USED ALOT ON V-DUBS

on V-dubs? never seen that, but I have seen it on like 54 chevy trucks, and some older cars in that era... swamp cooler? hows that work on a car like that?

yes it is called a swamp cooler. you it clips to the top of your door window that you roll down about 3 inches. there is a slot that comes off the tank and shoots in that spot of the open window and you will the tank full of ice and the air driving down the road blows over the ice. hope this helps.

you put ice in it then when air goes it in it blows cold air in.