Make your Gold Cube 3-stack a 4-stack or make your 4-stack a 5-stack! If you need to replace an original tray, this is what you're looking for.
Unlike the blank trays, the solo trays feature vortex matting just like the original trays. Many experienced prospectors will use an additional tray to switch out while they are running their Gold Cube as a high banker out in the field. This allows for more run time since you can alternate the upper trays.