Although unopened, please understand that the packaging has some discoloration and dirt due to its age. The following is a quote from a commercial website: We believe that the thick, resilient sound of 50's and 60's vintage guitars is due not only to the saddle, but also to the tremolo springs. Current springs are often manufactured to be stiff and have strong tension, which differs from vintage ones. You will first notice the difference in the outer diameter. We found that vintage springs are 0.8mm thicker than current ones. We measured the tension of vintage and current springs from several manufacturers and derived a value close to that of vintage springs. Assuming use of 5 or 4 springs, this provides a change in weight and stability of arming due to the spring's contraction rate, resulting in an exquisite sense of torque. Furthermore, the increased weight produces a thick, resilient sound and a good reverb feel. We analyzed and researched vintage originals with the spring manufacturer to derive that warm, thick tone. Of course, it can also be used as a replacement part for current reissue guitars, etc., and those who do not own vintage guitars will be able to enjoy its performance, which is closer to the real thing. Wire Diameter: 1.3mm Overall Diameter: 8.86mm Nickel Plated