A ballistic grade is a specific combination of ballistic materials set by the manufacturer. These are layered and woven together in a precise number of layers and in precise order to meet an exacting NIJ protection level. Depending on the grade, there are differences in weight, flexibility, thinness, and cost of the ballistics.Please feel welcome to call at 1-888-884-2427, email us or message us with your question. If it happens to be after business hours, emails will be seen in the morning and answered in the order they are received.