Mouse Included: No Palm Rest: N/A Normal Keys: 104 Operating System Supported: Windows 98 or higher, or OS/2 Features: 104-key layout with Large L-shaped Enter key Three Windows keys Low-cost, high-quality center-bearing membrane switch This product meets the European Union RoHS initiatives. Now shipping with Ergo Technology. Most keyboards use a standard 55 grams of force required to register every key, Ergo Technology has 5 different levels of force. From 35 grams to 80 grams - that correspond to the strength of the finger that touches the keys. The result is more comfort for your hands.