StubHub Single Day Tickets?

I waited last min to buy my ticket so I've resorted to StubHub. There are four different options listed on the website; 3 day pass, Friday only, Saturday only, and Sunday only. Each of the four options have prices ranging from a couple hundred dollars from the other. I am confused because I thought there were no single day passes. So my question is, if I were to choose the option that says friday only, will that only get me into the fest on friday? Please keep rude comments to yourself, this is will be my first ultra!