These V-shaped Plug Inserts Professional Seedling Trays are used by commercial growers. While they can be inserted into No-Hole Flats, they are intended to be placed on a propagating table so air can circulate under the tray and the roots stay in the plug. Use to start lettuce, members of the cabbage family, onions, flowers, etc. in a greenhouse or outdoors. To remove transplants you can pull them out (after watering). Inserting a piece of 1/4″ dowel into the drainage hole also works well to dislodge the plugs. This is a 128 cell tray.