Velcro learning app With the free Klett Learning app, you can use the digital products as well as audios and videos for your textbook on PCs, tablets and smartphones, even without an existing internet connection. • Easy registration in the app with the Klett access data for students and teachers • All licensed digital products are displayed at a glance • After downloading into the app, the products can also be accessed offline • Activate new products by entering the license code or user key