Parametric proximity card holder for lanyard

Update 2024-11-17: After ~3 years of near daily use, it broke. I've made a few subtle updates to the model that should both strengthen the fracture point, and clean up a model a bit.

I had used an older design daily for a year, before it broke. This new improved design should last much longer. Only a few millimetres thick, light, and open on both sides. Best printed with a small layer height - I used 0.1mm. No supports or brim required 

https://cad.onshape.com/documents/80a395d6db46f1b6c9dcff84/w/2072bb364bb2347d5d51b18a/e/92523384b55267b187675a6b