If you have a Fender guitar or re-issue from the 1950s-60s or 70s, this is your nut! A 7.25" radius, works with a curved or flat bottom and is permanently lubricated for great tuning stability. It works in both a flat bottom or curved bottom nut slot due to its ingenious design, sand off the tab for a curved bottom. It is pre-slotted to make for a quick and easy install. For just about all Fender electric guitars made in the 1950s, '60 and ’70s… that’s a lot! The 7.25” fingerboard radius originated in the early 1950s and was used for most Fender electric instruments until the 1980s. In the 80's it was changed to a slightly flatter 9.5" radius.