USI Protocol: USI official certification, works with any Chromebook that supports the USI protocol. What You Get: 1 x Pen for Chromebook. If you any question with your purchase, please feel free to contact us, we are here to help, either arrange a free replacement or full refund. Long Battery Life: This USI pen for Chromebook can last for 150 days based on 2 hours active use daily. There is no button so this could avoid mistouching (Button function is disabled on current Chrome OS). 4096 Levels Pressure Sensitivity: This USI pen is great for drawing and writing and editing, provides an industry-leading 4096 levels of pressure sensitivity for natural writing and sketching. Widely Compatible: Compatable for Chromebook, including Chromebook C550-13, Duet Chromebook, 10e Chromebook, etc.