The otion that does not work for me is the needle threader, I think by clover. Other poeple have had success with it, but I have had two and neither one has worked for me.
One other notion is Omnigrid yellow marked rulers, they give me a headache because they are too busy for me. I just bought the frosted rulers and love them.
Also I have bought several marking pencils that were recommended, didn't work for me.