Razer LACHESIS Master Manual page 7

Forward
Assign a "Forward" command in Windows Explorer / Internet Explorer.
Backward
Assign a "Back" command in Windows Explorer / Internet Explorer.
On-The-Fly Sensitivity
Enable change of sensitivity settings on the fly without the need to enter the configuration menu.
Single Key
Activate a key on your keyboard.
Scroll Up
Scroll up the page you are currently viewing.
Scroll Down
Scroll down the page you are currently viewing.
Button Off
Disable any function on the assigned button.