The file 'Parametric Pulleys 3D Printer Model' is (scad,stl) file type, size is 48.5KB.
This is a remixed version of http://www.thingiverse.com/thing:16627, with a even better user-friendly interface in Customizer app.
If you want just the scad file, you can get it on the original page.
Edit 04/12/2015:
parametric_pulleys.scad | 18.8KB | |
parametric_pulleys_GT2_20.stl | 572.3KB |