User blog comment:Derek34/Portable wall/@comment-8667564-20130424205856

Ok, I built a wall expecting that it could be added as a defense. I usually see that there is a limited number of fighting units to be fielded  plus some defense units, like a bunker or phillbox, armored pillbox, when repelling an invaider. But when attacking an invaider or raiding in someone else's land there are no defense units available, even if you have a portable wall in you inventory. Plus it requires tier 4 resources to repair. You only need tier 3 resources to build.

This item must be a mistake. It's not logical. It's not usefull. It is a waste of resources and time.