Mobil 1 M1-103 - Spring???

[Points]

What is the spring on the bottem of Mobil 1 103 filter for? I seen this before on friends car filters but not any of mine. I have a new Vibe (5,000 miles)with a 1.8L Toy. engine and i have been using Motorcraft FL400 but today i installed the Mobil 1 filter.

Thanks

 

[Palut]

I believe that its the bypass valve. Oil pushes on it towards your eye, and when pressure gets high enough the spring slowly lets the valve open.