In our drop-down menus for adding to cart, we show the gauge of the item you are ordering, then the length/diameter, then the ball size if it has any:

14g - 3/4 inch (5mm balls) 6g - 1/2 inch (8mm balls)

Jewelry is measured through a gauge system (see chart below). The higher the gauge number the smaller the wire is. A standard "earring" is usually 20 gauge. Jewelry gauges/sizes can vary between manufacturers. There is no universal regulation on companies to make a standard size in body jewelry. A big part of this is that some jewelry is made overseas and measured in millimeters. And in the USA jewelry is measured in inches/gauges. So many times jewelry can be anywhere from .5mm to 1mm different.

CONVERSION CHART:

Gauge	Millimeter	Inch
16g	1.2mm	3/64"
14g	1.6mm	1/16"
12g	2mm	5/64"
10g	2.4mm	3/32"
8g	3.2mm	1/8"
6g	4mm	5/32"
4g	5mm	3/16"
2g	6mm	1/4"
0g	8mm	5/16"
00g	9mm to 10mm	3/8"
	11mm	7/16"
	13mm	1/2"
	14mm	9/16"
	16mm	5/8"
	19mm	3/4"
	22mm	7/8"
	25mm	1"
	26.9mm	1-1/16"
	28.5mm	1-1/8"
	30.1mm	1-3/16"
	31.7mm	1-1/4"
	33.3mm	1-5/16"
	34.9mm	1-3/8"
	36.5mm	1-7/16"
	38.1mm	1-1/2"
	39.6mm	1-9/16"
	41.2mm	1-5/8"
	44.4mm	1-3/4"
	47.6mm	1-7/8"
	51mm	2"

Enlarged example of 1" on ruler