This necklace has 3 sterling silver triangle charms that hang loose on the chain. Each triangle measures 6.5 mm (small). The chain is a 16, 18 or 20" rhodium plated, sterling silver Italian box chain, from Italy.
 
This specific necklace is shown on the model in the second picture wearing a 16" chain. 
In the first she is wearing the 16" chain (the shortest necklace). The middle necklace is an 18" length and the largest circle necklace is a 20" chain.