Bracelet sizes are listed as circumference in cm. To measure your wrist use a measuring tape or wrap a piece of paper/string around your wrist and measure the distance between the two points that meet with a ruler.
Small = 16cm (6 inches)
Medium = 17cm (6.7 inches)
Large = 18cm (7 inches)
Extra Large =19/20cm (7.4/8 inches)
RING SIZES
Size 6 - 53mm
Size 7 - 54mm
Size 8 - 58mm
Size 9 - 59mm
Size 10 - 62mm