Worm Factory 360 Composting Bin + Moisture and pH Testing Meter Worm Farm Kit (Black) The Worm Factory 360 has a standard 4-Tray size which is expandable up to 8 trays, giving it the largest volume of any home composter. The redesigned lid converts to a handy stand for trays while harvesting the compost. Included instruction manual with step-by-step directions for managing your Worm Factory 360. Moisture meter, pH meter, and thermometer help eliminate any guesswork and allow you to optimize the worm composting process. Built in "worm tea" collector tray and spigot for easy draining.