Size tubing and fitings different...*PICS*

[BstOnTheBrain]

I just got my case with the WC kit about a week ago and its just been sitting in my room so i decided to open it up and make sure everything is looking good. So i opened it up, set everything out and started looking at the radiator and the kit and tubing fittings and what size it was. Now when i bought it i read it and it said that "This Koolance system uses 3/8 fittings" so i thought i would get all 3/8 hardware etc. But now i look at the tubing on the radiator and it looks pretty big; possibly 1/2?. Then i look at the extra tubing that came with the WC and it looks much smaller. The hardware that came with the kit came with 2 F-like splitters that take in 2, 3/8 hoses and then connects 1/2 hoses. I think the extra 3/8 hose and connectors are for connecting only Koolance products seeing as how this is a Koolance product. But i dont want small tubing to hinder my rig. So im confused on what type or size i should focus on. If i can use the biggest, i will

this is the tubing from the radiator that came attached etc..

then this is the extra tubing that came in the WC box w/ the fittings..