This bracket has two functions: 1. to hold an iPhone and SQM-L meter with a fixed alignment between them, so that the iPhone screen can be used to assist aiming the SQM at the zenith; 2. to allow the SQM to be fixed to a tripod or monopod. It is especially useful when used with the free iOS app SQM Mobile. Here's the link on the US App Store: https://apps.apple.com/us/app/sqm-mobile/id6753923113

As well as the 3D printed part you will need:
2x #4 x 1 inch self-tapping screws, countersink heads
1x 1/4 inch UNC nut (which is the correct size to accept a standard tripod screw)

To fix the bracket to the SQM-L you must remove the 2 case screws by the battery hatch (furthest from the optical end), and use the 1 inch #4 screws to fix the bracket to the SQM-L. The 1/4 inch nut is a pass-fit into the hexagonal hole in the base.

There are two pegs which can be used to fix an elastic band in place which can secure the iPhone in place. I have found that the small elastic bands used to bundle asparagus bundles here in France are a perfect fit, at 5mm wide. But in fact I don't use such support as it's easy to hold the iPhone in place by hand long enough to make the measurement.

I've also found that a monopod is quick and easy to use. A tripod also works but is more cumbersome to set up.