biggest to smallest, 12, 13,14,15,16........the 12s are rarely used unless u want to jump gauges on ears, 13g and 14g are usually used for 14g body jewelry and 15g and 16g are usually used for 16g body jewelry. The only reason i use a 13g for a 14g piercing would be because it allows u to stick the jewelry end into the end of the needle to it can be followed threw easier same with the 15g needle for the 16g piercing. Thats just for those of you that might wonder why i have many different sized needles..