We recently tried these in a custom shop Fender and we could not believe the difference ! The wear and tear of parts from vintage guitars that were manufactured few decades ago can cause functionality problems. What vintage guitar users fear the most when these parts need to be replaced is if it will cause the sound to change significantly. Tremolo Springs are a part just as vital as the saddle and they are responsible for the fat sound of the 50s and 60s Stratocaster. Most newly manufactured springs have different characteristics from the vintage. They are hard with strong tension. As one of the raw vintage product, they researched the vintage and matched the tension of the spring. And with the prerequisite of using 5 or 4 springs together, they were able to achieve superb torque feel and stabilized arming that were made possible from the difference in weight and contraction percentage. And with the increased weight, Raw Vintage were able to create Fat Tone. These can be used as a replacement parts for the new reissued guitars, enabling their owners to enjoy the characteristic closer to the original. We recommend you to use this in a set of 5.