This tools is used to un-jam a 1.75mm extruder. It will push material through a hot extruder. It can also be used to align the extruder during assembly. The rod is a standard 2mm bike spoke.Print the part at 80% infill. Go to the local bike shop and ask for an old used bicycle spoke, they come in several sizes including 1.7 mm and 2mm I used a 2 mm. Cut the spoke in half with a hack saw,(do not use wire cutters, they will deform the spoke) file the ends to make them flat and remove all burs sharp edges etc. Glue the spoke in to the handle you printed and you are done. The new tool can be used as a plunger for stuck or jammed filament that is down in the extruder. You can also use the tool to align the extruder you should be able to poke the metal spoke through the extruder and all the way down to the hot end. If you encounter resistance use the spoke to figure out how deep it is and find the trouble spot. There should be a smooth clear path from the top of the extruder all the way to the hot end if every thing is aligned properly. PLEAS NOTE 1.) Most bike shops will give you a few spokes for free, remember to thank them and tell them what your are doing with your spokes! ( it is good PR for our community and it is polite) 2.) If the hot end is on when you shove the tool in the spoke will get hot! be careful not to burn your self or melt things accidentally.