Expand your Worm Factory 360 with a Worm Factory 360 Single Tray - Black. This tray is constructed of recycled high density polyethylene and measures 16" x 16" x 5". The Worm Factory 360 can be expanded to 8 trays total. Four trays normally provide enough room for the kitchen waste of a family of 4. Each tray averages to be about 12 pounds when full of compost.