In order to creat a very unique Bajo Quinto set, we have used three different materials which are stainless steel, phospher bronze and nickel plated. .060 & .080 - Hi-Beam stainless steel bass strings are round wound and constructed upon a round core with loop ends. Both of these strings provde highly flexible and musically bright string. .026, .036, .046, .030 - All of these strings are from our Zebra series. Every other coil is nickel plated steel, every other coil is Rare phospher bronze on a round core with loop ends. *Absolutely great for Bajos equipped with a variety of pick-ups such as piezo pick-ups or magnetic pick-ups."