Sales estimate is based on BSR of the product.
We cannot predict the sales of products that have a high BSR. A high BSR means low product sales. The application shows the estimated number of sales for products that have a BSR below 400,000 (this means between 1 and 400,000). But for each category, this figure may be different. With a small number of sales (when a product has a high BSR), focus on bsr drops. This will tell you the estimated number of product sales.