What is the size of the headphone jack on a MacBook pro
I read that I could convert my cassette tapes to mp3's by connecting my cassette player to my MacBook Pro. I need to buy cables to do this, but I don't know what size will fit the MacBook headphone jack. It seams there are several different sizes on the market.
MacBook Pro (13-inch Mid 2009), OS X Yosemite (10.10.2)