I have built a sewing kit in both the plastic breath-strips box and the metal Altoids breath strips box. The plastic box has a somewhat easier shape to fill since it lacks the little Indent on the bottom that the Altoids provides to make it easy to pull the tray out. I even found some plastic ones that operate as a tray without the space-wasting little indent. OTOH, I don't trust the plastic "hinge" on those plastic containers. OTOOH, the plastic containers can easily be snapped apart for use allowing unfettered access to dumping the contents all over the ground - or, in the case of a fishing kit, into the water.