The self-watering accessory is an optional insert for your Classic VegTrug, which sits beneath the compost and continuously supplies water to all your plants. The funnel features a cover to prevent any solids from entering the reservoir below and a fill meter to make sure your VegTrug never runs dry.Compatible with the small or medium Classic VegTrugLarge reservoir can comfortably support your plants for days at a timeCovered funnel prevents solids (and critters) from falling into the reservoirFill meter ensures your VegTrug never runs dry