Expand your VermiHut Worm Composting Bin with a VermiHut Single Tray - Black. This tray is constructed of high density polyethylene and measures 16" x 16" x 5". Each tray holds about 1200 worms. Three trays normally provides enough room for the kitchen waste of two adults. Each tray averages to be about 12 pounds when full of compost.