Minecraft wiki entry for Miscellaneous, associated text: Variations: The player can remove one of the items from the dropper to create a 2-RNG with different power level outputs than the regular 2-RNG: removing the 64-stackable item outputs power levels 2 or 4, removing the 16-stackable item outputs power levels 1 or 4, and removing the non-stackable item outputs power levels 1 or 2.