Our Wormeries work by harnessing the surface feeding nature of the hungry tiger worms contained within. This happens naturally as it\'s a trait of these composting worms to live near the surface rather than deep into the compost. However, by adding a moisture mat to your Wormery you make it easier for the worms to find the surface and encourage them upwards. They can also help prevent occasional fly infestations by adding another barrier to the outside world. Simply pop a damp mat on the surface of the food waste in your Wormery and leave it there.When you add new food waste, add it just underneath the mat. The mat, being made of Coir and being natural will eventually degrade and be eaten up itself by the worms, leaving behind a rich organic vermicompost. Our Moisture Mats are available in the following sizes (cm) to fit each Wormery: Junior Wormery (Round) - 25cm (w) x 1cm (d) Midi Wormery (Round) - 29cm (w) x 1cm (d) Indoor Womery (Stainless Steel) (Round) - 29cm (w) x 1cm(d) Rainbow Wormery (Round) - 29cm (w) x 1cm (d) Original Womery (Rectangular) - 34cm (w) x 40cm (h) x 1cm (d) Tiger Womery (Square) - 36cm (w) x 1cm (d)