THIS IS A 23AWG SIZED SINGLE STRAND HOOK-UP WIRE. THE WIRE’S CONDUCTOR IS MADE UP OF TINNED COPPER AND IT IS PVC INSULATED TO PROTECT IT FROM ABRASION, CHEMICALS, OILS, AND SOLVENTS. ITS YELLOW COLOR ALSO HELPS FOR EASY CIRCUIT IDENTIFICATION. 

It is a perfect wire for breadboards, Arduino, or any other application of frequent cable use.