The Universal 4 Pin Buckled Cable is made for the Grove System to connect all of the Twigs to the Stem - Basic Shield or to other Twig compatible boards for quick prototyping. As a lot of users ask for different length of cables, so we made the 5cm, 20cm, 30cm, 40cm and 50cm cables for different applications.The 20cm cable is in default included in the Grove - Starter Bundle.DocumentsPlease visit our wiki page for more info about this product.It will be appreciated if you can help us improve the documents, add more demo code or tutorials. For technical support, please post your questions to our forum.