Does anyone know the exact size of the rear windwscreen wiper hole in the rear window?

I know there is a How To Guide on here, however i'm looking for the specific hole size details in order to locate a Glass Window bung. To save me taking apart the car before I order one - anyone happen to know the dimensions?

These look far more OEM in my opinion so i'm looking at some options: https://www.killallwipers.com/products/

Thanks