I used these to thread sewing needles from large to small. The large sizes, 4, 5, & 7, threaded easily with this threader. Size 9 required a tiny "pop" to get it out again once threaded. The size 10 also required a bit of extra poking and pulling, but it worked. But these were all Dritz needles. When I tried it with my all-time favorite quilting needles, "Foxglove Cottage Quilting Betweens, Size 10", it didn't work. The eye must be smaller. Luckily, I've found that Gutterman hand-quilting thread is the one thread that will willingly go through the eye without using a threader, so I'll keep using my favorite needles with Gutterman thread until I can find a threader that will work with very tiny eyes.