These EVA foam plugs slide onto needles (all the way, not just on the tip) to prevent your stitches from sliding off. 

They are also handy for slipping onto interchangeable needle cords to keep your stitches from sliding off while you try on your top-down garment or use your needle-tips elsewhere.

Mixed (grey): 4 each of 6 sizes, suitable for cords and needles sizes US 0-15 / 2-10mm.

Large: 4 each of 3 sizes, suitable for needles from US 9-15 / 5.5-10mm.