This thing is a two part iPhone 6 bike mount. One part is strapped to the handle bars using cable ties. The other is a case for the phone. The two parts allow a simple 1/8 turn snap lock to securely mount the phone. Removing it is just as easy.
I printed this in PLA and the first few engagements were a bit stiff, but after that it gives a reassuring click and holds the phone nice and firmly.
I used a strip of rubber from an old inner tube as a liner under the mount so that the mount doesn't slip on the handlebars. A video of the installation can be seen here: https://www.youtube.com/watch?v=kGJIT41Z6Ys
The model has a first layer inset to prevent a bulge forming on the bottom layer when it is set a bit low for good adhesion. This is based on a first layer height of 0.3mm, but it is easy to change in the OpenSCAD if you use different settings.
The walls of the case are exactly 2mm to allow 4 passes of a 0.5mm nozzle.
This was designed in OpenSCAD making good use of the minkowski, projection, hull and offset functions.