130/705H are backwards compatible with 15x1. 130/705 is the needle system used in most modern machines. 15x1 is used in many vintage machines, but may not work with modern machines. If your packet says, "HAx1, 130/705H, and 15x1" you can use them on nearly all your machines, vintage and modern.
And you are not an idiot. I didn't know about the different needle systems until I took Ray White's classes in sewing machine repair.
Last edited by k9dancer; 09-29-2012 at 06:08 AM.