Tray inserts are plastic and made to fit a base tray, that can be placed on a heat-mat or under lights. They are sold by cell size- the number of cells tell you the individual number that will fill the kord tray.
12 cell: 18 cell:
24 cell: 36 cell:
48 cell: 72 cell:
Plastic Inserts,6 sizes for Propagation Trays
