Google Calendar Pro is an extension for the Firefox browser that provides access to your Google Calendar right from your browser. It offers a range of features that go beyond the basic Google Calendar, such as the ability to set multiple reminders, customise the calendar display, and more. It also allows you to easily manage your events, sync with other Google services, and even embed your calendar into your website. With Google Calendar Pro, you can easily stay on top of your schedule and make sure you don't miss any important events.