This can only be used on line level promotions.
This offer type can be used to alter the value of a product/s.
E.g. If you buy this product it will be £15.00 rather than £20.00
Based on the breaks, you're also able to set the product to be different prices based on whether a customer is purchasing more of less of a product.
I.e qty break 1 could set an items price to £15.00 per item or and Qty break 2 could set it's price to £10 discount if 10 or more were being purchased.