2" NPT cap for Maxbotix USB ultrasonic sensor (oil tank level readings)

I found the [Maxbotix](http://maxbotix.com/) ultrasonic sensors to be quite good for monitoring the level in our home heating oil tank, but up to this point I was buying a 2" NPT PVC pipe plug and swapping that into a blank spot in the top of the tank. This required careful drilling of the pipe plug, and the end result worked but didn't look good.

This thing started out life as a a 3D model from [McMaster-Carr](https://mcmaster.com/), which I modified with provision for the [Maxbotix USB sens