This 17 inch (435 cm) chain (inclusive of clasp) is handcrafted from Argentium silver and has a handmade sterling silver lock charm which is secretly an 8 gigabyte thumb drive. Each link is individually soldered, filed smooth, hand formed, assembled as a whole, pre-polished and drum turned for strength and sheen. The charm is shaped and soldered from sterling sheet & wire before being drum turned with the necklace. Lastly a tiny usb card is secured inside the charm and tested to assure it works. It's a necklace with a secret.