I created this balloon pump holder for the Borosino Little Genius balloon pump sold on Amazon.  It comes with it's own carrying case, however, it smothers the vent holes and can cause the pump to over heat.

I created this model in Fusion 360 and I've uploaded the STL, fusion files, and step files.  Please feel free to adjust it to your liking.  
The Fusion 360 model is all parameterize, so you can easily redemension it via parameters.

I created mine on by Bambu labs X1 Carbon with PLA filament.  I used slim tree supports which were easy to remove.  I made mine at 100% infill for the benefit of the belt loop strength.
But you can try it at 25% or 33%.

It took 5  hours to print at 100% infill.  At 25% infill Bambu Studio calculated 4 hours to print.

https://www.amazon.com/gp/product/B07TB37S9M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1