A sealed unit includes at least two sheets of transparent or translucent material separated from each other by a spacer. One example of a spacer for a sealed unit includes a first elongate strip, a second elongate strip, and filler arranged therebetween. The first and second elongate strips have a small undulating shape in some embodiments. Methods of making spacers and window assemblies as well as devices for use in the manufacture of spacers and assemblies are disclosed including a manufacturing jig and a spool storage rack. The spool storage rack stores a plurality of spools configured to store spacer materials thereon.