Material: Plastic Size: 13*9*1.2cm Number of keys: multi-function 19 keys Telescopic line: 70-80cm System requirements: WindowsXP.Windows7/8/9/10, Linux, Android system, Apple system, etc. Features: 1. Waterproof, oil-proof, font wear-resistant and not fade, waterproof, oil-proof, font wear-resistant and not fade. 2. The overall shape of the keyboard is designed according to ergonomics. The slightly inclined shape reduces hand pressure and the keys rebound quickly and are not sticky, providing a more comfortable touch for each keystroke. It is not easy to get tired and more comfortable for long-term use. 3. Human body comfortable button structure, anti-slip, anti-drop, not easy to wear, sensitive touch, comfortable hand feeling. 4. The slim design can be easily put into a briefcase or notebook bag for easy portability, meeting your mobile data input needs at any time