Popular STL Files for the Di3 Home / Popular STL Files for the Di3 Here is a list of popular or recommended STL files for use on the Wanhao Duplicator I3. Z Braces and the Guide for Installing Bearing Blocks for the Standard 8mm Bearings Bed Leveling Knobs Bed Leveling Knobs with Numbers Adjustable X Block and Attachment Adjustable Y Axis Fan Mods: Cobra Cooler / DiiiCooler / Circular Cooler