i have been looking through previous post and have seen many diffrent sizes i would like to know the size of the input jack on a 2008
That's just one of many problems with the Owner's Manual (although I'm not sure that the Prius manual is worse than others since the Prius manual is the first manual I've ever bothered to read in any detail). However, although it doesn't say it is the 3.5mm size plug, it does call it by its common name, "mini plug" (note that the smaller 2.5mm size plug for cell phones is sometimes referred to as "submini plug").