When choosing your correct length. All you have to do is take a piece of string and lay it around your neck, like how you would like to wear this necklace. Then measure the piece of string. Everyone has a different size neck, so be sure to measure yours!
The necklace is made with a synthetic star fish that can be worn in water. I would suggest cleaning your necklace if it comes into contact with any chemicals and rinsing it after days in the salt water or a days in the gym. The chain is sterling silver and can be polished back to its original shine easily with a simple polish.