This is a knob designed to encase a 1/4" hex nut to create a threaded knob for use on a threaded stud. It can be used in a wide range of application where you need a hand securable knob on a carriage bolt or threaded rod.The nut is inserted into the knob during the print run. It takes a little calculating and watching, but you can watch and pause the print when it has printed the last of the layers that make up the hex recess. If you are printing with 0.4mm layers, it will be after approximately the 25th layer.It is designed for a 1/4-20 nut but could also be used with a 6M nut if printed at approximately 95%. Untested, but it should work with a range of nut diameters by changing the print size.