I just tested this product, The tool is printed on a 3D printer and the overall quality of the print is only average. The smaller one seemed to work okay but was not near as easy as the video made it look. The Larger one work to a much lesser degree. It did not seem to be able top press in the retaining tab very well on the on the connector. over all well the concept seems sound the quality of the tool is preventing it to work as well as hoped.
Calvin, Thank you for your honest review. I think I need to add operating procedures in the text. I found that after inserting the connector applying slight tugging to the wires while applying slight squeeze/release pressures to the connector will reliably release the Terminal Pins. I have succeeded on every connector I have around here. However, I have discovered that many "knock-off" JST connectors have different "Crimp Profiles" on the Latch part of the Terminal Pin that does not match the flat design specification on the JST Datasheet. If you could mail me the connector your having difficulty with I would gladly use it to make modifications to the design and return it and the new extractor at no charge. By the way, the 3D printed parts are structurally sound and high enough resolution to do the job.