First of all, i am satisfied with your products. All our work stations are your products. My only complaint is one of our m510 mouse just stopped working. We tried everything but to no avail. The only thing is that it must be defective, since the rest are working fine. Went to two places but can't find another one. Not even sure a new one will sync with the keyboard gene chavis ea/aba [protected]@aol.Com