However- I thought the Interchange system would allow it to work with my Columbia Ballistic II fleece. It does not. The fleece will not zip into the shell. I finally went to a local store that sells a lot of Columbia products and found a fleece for $55 that would work perfectly. The penny pincher in me told me to put it back and just wear one of my existing fleece jackets underneath without worrying about the zip in feature. So- I saved the $$ and walked away from it.The shell is good- it sheds rain like a champ and is pretty wind proof. The pit zips help regulate the temperature. I can see no actual benefit to the foil-like material on the inside that is supposed to trap heat.The takeaway- a good shell- but Interchange does not necessarily mean what it says. Buy with caution if you are mixing and matching.