Twisted Steel Wire Needles are versatile, easy to thread, and great for stringing, but are not as durable as English beading needles.
Size 6 twisted needles (extra fine) fit O, A, B and size 1 bead cord.
Size 8 (fine) fits C, D, E, EE, 2, 3, 4, and 6 bead cord.
Size 10 fits, F, FF, 5 and 8 bead cord.
Size 12 fits heavier cord.
English Beading Needles are commonly used with seed beads, and for bead weaving. They are springy and durable. Like seed beads and wire gauges, the larger numbers are thinner diameter, so size 15 is skinnier than size 10.
Size 10 beading needles work well for larger seed beads (sizes 10 and 11), and for bead thread size D and smaller.
Size 15 is for very fine cord and/or multiple passes through small beads.
Big Eye Needles are great for ribbon, yarn, and twine.