Pay Attention: If some keys will don't work after installed ,this is not because keyboard is broken ,the most posiibility is ribbon cable don't connect well with your laptop ,pls try to reconnect more times .Many customers solve this problem after did this. We tested every keyboard before shipping ,please be assured the purchase. thanks *Backlit : No *Color : Black *Layout : US keyboard layout *Status : Brand new Compatible Models: for HP ProBook 4540s 4540 4545s