Probuilder Mesh Collider Size

Hi, before I used probuilder I created a cube using the built-in 3d object. Because I wanted to generate a bunch of the objects at run time, my script used the bounds size of the render / collider. After using probuilder for the object however, the sizes became (0,0,0). I'm not sure how probuilder works, but given that the mesh collider uses the probuilder mesh shouldn't it know the actual size? I also don't know how to access the object size in the pro builder mesh script component.

I have tried looking for answers, but surprisingly I didn't find anyone with similar issues. Excuse my ignorance if I am missing something obvious, I am new to Unity.

Thanks