NOOB wondering how to place an order..

Hi!
I am about to place an order for the Hifiberry, but I have a perhaps stupid question.. On the ordering page I'm not sure what to specify when it comes to the "Raspberry Pi connection". What does it mean by "I2S + 26pin"?

What I want is a Hifiberry with a low profile 3,5mm audio jack (No RCA's), the 8 pin connector (that I will solder to the RPi) + a nylon spacer and all the SMD parts to be soldered.

Should I then choose the "Raspberry Pi connection" as "None" or?

Thanks! =)