Crimson seedless grapes have found a following because of their amazing sweetness as well as their incredible shelf life.  They hold up longer in storage than almost any other grape which makes both the supplier and the customer happy. 

The color on these grapes is paler than the flame seedless and tends to be a light red or pale purple color.  Their sugar content is extremely high and split about evenly between sucrose and frutose which will give you both instant energy as well as a sustained source of energy.  That's why fruit in general is a much better pick me up than a candybar or a cup of coffee that only contain sucrose and will cause you to crash eventually.  Have a cup of grapes instead.