UPDATE: Was $450.
According to an article from JP Magazine, the WAT was sold by Warn in 1969 and intended to slip between a T-18 and a transfer case. The writer of the article only remembered ever seeing one of them.
“The war in overdrive unit shift good and bolts between the T case and the transmission. I am asking 450 but open to offers. Was going to use in a Dodge pickup to get rid of the automatic but my plans have changed.”
I found this ad in the May, 1969, issue of Popular Mechanics.