Mid layers are an insulating layer that work by retaining your body heat to keep you warm. These are the hoodies and pullovers I've used and recommend for hiking.
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest
I Heart Pacific Northwest