MacOS screen annotation/presentation software

I was going to write a little application to let me annotate my MacOS screen during presentations, but the Ink2Go product looks like it does exactly what I was thinking. As I’m creating a video presentation, such as when showing how to write some Scala or Android code, I want to be able to draw on the screen, such as writing text, arrows, circles, and boxes to highlight parts of the screen. Ink2Go looks like what I want. There are some other products available, such as Screen Marker.