Heavy duty support for other seedling containers. Used with six-pack jumbo plug flats, square plastic pots, biodegradeable pots, and other traditional inserts to create compact, efficient growing systems for bedding plants, pack sales, herbs, seedlings, and vegetable transplants. Heavyweight injection-molded polypropylene construction with a narrow uniform bottom mesh and solid side walls. Offers maximum strength to support inserts uniformly without sagging in the middle for uniform watering. Compatibility: Use with Pro-Trays, Jumbo Plug Flats, and Mini Square Plastic Pots. Dimensions: 10 1/2" x 20 7/8". Black.