This is a box of six 25ft spools of stranded-core wire. Stranded-core wire is best used for wiring jigs where there's bending or movement expected. It also works well with terminal blocks. It's not great for use with breadboards (without tinning). The wire is easy to solder to, and when bent it keeps its shape pretty well. We like to have a few spools of this stuff around which is why this set is quite nice! We suggest picking up some wire strippers to match. Wire gauge is 22 AWG, which we've found is the best all-around gauge.
This set is not good for breadboarding! For breadboard use, check out the solid-core wire set
The box has a plastic dowel rod to hold the spools in place and let them spin, and there are little punch-outs you can pass the wire through so it'll stay nicely organized.