Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:1963172.
Mounting base for FHKSC Flow Sensor Model #932-952x/Bxx, manufactured by Digmesa AG. This flow sensor is typically used in Espresso Coffee Machines to measure the amount of water dispensed by the machine.
The datasheet for the flow sensor is here: http://www.digmesa.com/wp-content/uploads/932-952x_Bxxx_GB_20V-2.pdf
This has 2 countersunk holes and a flat base for mounting (could be fixed with single, double screw or adhesive). The sensor is intended to push fit in and locate in two possible orientations on the top surface.
The sensor mounting holes are 12mm apart and 4mm and 2.85mm diameter, and the top plate 2.5mm thick. The mounting holes are 20mm apart and 3mm diameter. Overall height is 9mm (conservative minimum). There's a gap underneath for routing cables.