What started as a novel curiosity has become all the rage and THE most effective and rapid tool to focus a telescope. It is now my principal method to focus after trying the Stiletto and focus metrics such as FWHM, peak Value, and radial width. This method has allowed me to take back literally hours of precious imaging time.
Bahtinov focus masks made from a "Handicapped Parking" sign from Home Depot and spray painted black with Krylon Fusion paint. Then using self-adhesive velcro pads, the foam blocks were attached to the telescope side so that the masks would stay in place on the dew shields. Not fancy, but effective.
Generate your own Bahtinov mask at David Polivka's Astrojargon
website. You will also need a copy of the freeware Inkscape
to read and translate the generated files if you don't already have software to open .SVG files.