This indicator is intended to provide market bias information at a glance. Depending on the number of periods selected it can help identify changes in buying and selling sentiment or overall market bias. The two lines indicate increases and decreases in volumes for the selected number of periods. I recommend using this indicator with a minimum of clear support and resistance lines and a standard volume indicator. It does provided useful information as a stand-alone indicator. I don't use any indicators except volume, so this was meant to be my own personal volume analysis tool, however I feel that it can be very useful for other traders who may not have a deep understanding of volume analysis.