For much of the 1930s, the holy grail of automotive technology was figuring out how to heat and cool the closed metal cabins that had replaced open-air cars. A few firms were able to fit huge coolers to vehicles, but it wasn't until this date in 1939 that Packard revealed the first air conditioning system offered direct from an automaker. The "Weather Conditioner" was a $279 option that required the Packard One-Eighty to visit a second factory for installation, since the unit connected to the engine and took up half the trunk space; Packard pitched it as not just for comfort but privacy, since riders could finally arrive without having the windows down. The option didn't sell well (there was no way to moderate the air from the unit) and Packard dropped it after 1942. Today, air conditioning comes standard on all but a couple of models — such as the base Jeep Wrangler.