Waves are promotional strategies that are extended over multiple periods.
Wave4 is a sustained blast that occurs over 4 consecutive days.
Wave7 is a sustained blast that occurs over 7 consecutive days.
Each day of a Wave is intended to sell the same number of units. Due to factors out of our control, the number won't be precisely the same every day. As an example if you give us 200 codes for a Wave4, you might see 53 units one day, 45 the next, and so on. There is a slight variation to each day. However the effect is still maintained.