Difference in Seal Material?

So I emailed Jon of Interslice, and he told me that he sends 2 types of materials, a foam, and a self adhesive velvet.

I'm curious to know, what are the differences of each material for sealing the camera? What pros/cons do they have?

The foam is typically used where vertikal pessure is to be found, as it is able to yield to to this (eg. at seal grooves, as mirror bumber at top of mirror box).
The velvelt is typically used where is less space and no vertical movement but slide or rotation takes place (eg. at door hinge).