The charms are sold in sets of three and are designed to be combined or added to other jewellery.
The pieces are made of gold- and silver-plated metal.
Here's some more information from Artecnica:
A new addition has been added to Tord Boontje’s iconic nature inspired jewelry collection of 18k gold and silver plated metal. This delightful collection embraces the delicate nature of fine jewelry in a playful manor, representing a loveable Penguin, butterflies and whimsical bubbles. These charms are sold in packs of three and are designed to be customizable allowing you to bundle a set on a chain or break the charms apart to further adorn any accessory.