You can mix and match any letters of the same size and color in a pack (or any digits of the same size and color). You cannot mix letters with digits or mix different colors of “letters” to create a pack. When ordering, please detail: 5x Letter: A, 8x Letter: C, etc. OR 6x # 1, 8x #0. Etc. Keep in mind that 16, is 1x #1 and 1x #6 (= 2 digits). Xtreme is hard surfaced, low friction striping material for new, smooth floors. Hard beveled edges help protect from pushed or dragged pallets, and shiny surface resists damage from turning and spinning wheels.