So, seed beads, as mentioned in a previous post, come in various sizes. They are written in “4/0 or 5/0” and are called “three o’s” (etc.); the smaller the first number, THE BIGGER THE BEAD. It used to mean that if you laid down a row of beads, end to end, the first number would tell you how many beads are contained in one inch. Typically, orisha beads will use 6/0 or 5/0 beads – especially in elekes.

Here are the /o measurements with their millimeter equivalents:

1/ 0=  6.5mm (Largest bead size)
2/0 =  6.0mm
3/0 =  5.5mm ( these are large and pony beads, crow, roller beads)
4/0 =  5.0mm
5/0 =  4.5mm (orisha bead)
6/0 =  4.0mm (orisha bead is a popular “e” bead and comes in the largest variety of colors and finishes, approximately 440 beads per ounce)
7 /0 =   3.4mm
8 /0 = 3.1mm
9 /0 =  2.7mm
10 /0 = 2.3mm
11 /0 = 2.1mm
12 /0 = 1.9mm
13 / 0= 1.7mm
14 /0 = 1.6mm
15 /0 = 1.5mm
16 /0 = 1.3mm
17 /0 = 1.2mm
18 /0 =1.1mm
20 /0 =1.0mm (smallest bead)

3/0 beads would be 4 per inch,
about 1/4 inch thick each.
6/0 beads would be about 8 per inch,
or 1/8 inch thick each.
15/0 beads would be about18 per inch,

You can also shop for beads and beading supplies on Amazon, here:https://www.amazon.com/shop/erinle

The above images are from Margola Corp in New Jersey https://www.margola.com/