Made this to hold my Woods timer for my bug zapper. To keep it water tight, it needs to be mounted face down, so I made this holder that can be zip tied to the pole as shown. It contains a peg that allows you to slip the timer over and down into the locked position.

Instructions

I am using a .35mm head and printing at .25mm layers. I used 40% infill, but it should work with your choice. Turn on support material to insure the top of the holding post is generated correctly and it will help the arch for the pole also. The cut out for the pole is 12.8mm dia which should be pretty typical. I've included the Inventor Fusion file so you can change it if needed or if you just want to play around with it. Enjoy :)