This will allow you to test toys for small children for potential choking hazards. It was developed by the US consumer product safety commission as part of their procedure here: http://www.cpsc.gov/businfo/testtoys.pdf I've also included a small section that has dimensions of the part to assure you've printed it correctly. I really wanted to make something my daughter could enjoy right now, but in researching how toys are found to be safe, I came across this part. While it's probably not expensive to produce, it's still cheaper to make at home I'd imagine.The procedure is very important here. Please read the above linked PDF. Once the part is printed, place the piece to be tested inside the tube. If it fits entirely inside the tube, then it is a choking hazard. Testing is done in conjunction with impact tests discussed at the link for 0 to 8 years old. Printed objects may seem large enough, but could easily break into smaller pieces so use caution.