in non-boot mode are free to implement an alternative HID profile. The above-mentioned behavior is in contrast to the PS/2 (not to be confused with PlayStation 2) interface, which supports n-key rollover (NKRO) for keyboards capable of supporting it. Mouse Computer mouse are another common USB HID class device. USB HID mice can range from single-button simple devices to multi-button compound devices. Most modern operating systems ship with drivers for standard HID mouse designs (the most common modern mouse design has two dedicated buttons and a mouse wheel that doubles as the third button); mice with extended functionality require custom drivers from the manufacturer. USB mice have lower latencies than PS/2 mice because standard USB mice are often polled at a default rate of 125 Hz while standard PS/2 mice send interrupts at a default rate of 100 Hz when they have data to send to the computer. Also, USB mice do not cause the USB controller to interrupt the system when they have no status change to report according to the USB HID specification's default profile for mouse devices. Both PS/2 and USB allow the sample rate to be overridden, with PS/2 supporting a sampling rate of up to 200 Hz and USB supporting a polling rate up to 1 kHz as long as the USB mouse runs at full-speed or higher USB speeds. Game controllers Modern game controllers and joysticks are often USB HID class devices. Unlike legacy game port devices, USB HID class game devices do not normally require proprietary drivers to function. Nearly all game devices will function using onboard drivers as long as the device is designed around the drivers and the USB HID class specifications. Other devices The USB HID class specifications allow for myriad other devices under the USB HID class. Some examples are automobile simulation controllers, exercise machines, telephony devices, thermometers, audio controls and medical instrumentation. Even uninterruptible power supplies and software protection dongles declare themselves under this class, despite the fact they often have no human interface at all. Any device can be a USB HID class device as long as a designer meets the USB HID class logical specifications. This is not to say that there is no need to ship drivers for these devices, nor that an operating system will immediately recognize the device. This only means that the device can declare itself under the human interface device class.