This works on the MK2S revision of the i3.
Model has been edited to allow clearance for the PINDA probe on the MK2S.
3 Top and Bottom Layers, 2 Perimeter Walls, .39mm Extrusion Width, Custom Supports under mounting tab are optional - the Prusa i3 MK2 and MK2S will print this fine without supports.
.39mm Extrusion Width assumes printing with .4mm nozzle. The interior walls will not print above .39mm Extrusion Width (in S3D anyway).
If you do not want the internal walls, try printing at .4mm extrusion width.
Do not print in PLA, it will warp and drag along your print.