For fishing enthusiasts who give credence to bite times based on Solunar Theory, this add-on can be imported into the Calendar in MacOS. As such, it provides a schedule of best fishing days for each month beginning January, 2018 and ending December, 2021. This add-on also works with the IOS Calendar in the iPad and iPhone. Please visit our website for further information about this item including the price and how to obtain it from our store.