The ERGO M575S is a trackball mouse - that means you don't move your wrist, just your thumb. Its ergonomic design will keep your hand and wrist in a natural position. So you stay comfy during long work days. And it's got quiet click buttons, which means you won't get dirty looks when you work in a library. Good to know - It uses a AA battery (that comes included) and a fresh one gives you up to 18 months of use - Use the Logi Options+ app to customise the 3 programmable buttons - For connectivity you can choose between Bluetooth and the Logi Bolt wireless dongle