Robust and durable

The Wunderkey add-ons are made of high-quality stainless steel, making them extremely robust and durable. With an extension set, the Wunderkey can be expanded by up to 4 additional keys or add-ons, or add extra sets stacked on top of each other, creating space for any number of keys and add-ons.

An extension set consists of a pair of extension screws and enough washers to fill in some space if you have an odd number of keys.