The Compost Duvet has been developed to prevent heat loss in the compost, especially useful in the early stages of decomposition. Heat builds up naturally and if it can be maintained it can destroy weeds, seeds and disease. This entirely new concept has proved to maintain high temperatures within the compost, both day and night. It will also keep out frosts in winter. The Duvet fits snugly into our wooden bins but it can be used on any compost pile or in any compost bin. Can be ordered in 2 sizes: 400 fits 400, 800 and 1150 Blackdown Range Wooden Composters 600 fits 600, 1200 and 1900 Blackdown Range Wooden Composters The 400L compost duvet can also be used to warm up your wormery during the winter months. The worms need temperatures of about 15-20°C and during the winter months the temperatures can drop below O°C, so in order for your worms to survive, a duvet such as this could be required to keep them warm and alive. Product image shows the Compost Duvets on a standard 400 Blackdown Range Single Wooden Composter which is not included. Please note - all UK Redwood timber has been high pressure and vacuum treated with preservative which allows for a 15 year warranty on our composters and raised beds. Colour of wood may vary from images shown as a result of the treatment process. Also note, you may receive your order and the timber may be wet, this can be because it has stood out in the rain during transit or it can be the timber has not dried out from the preservative treatment process. If the composter is received with the timber wet you may also notice some mould on the timber this will disappear when the timber dries and will not affect the operation or the warranty we give. This will not affect the use of the composter or raised bed, however there may be some warping and twisting of the timber as the timber dries. When timber dries out there may also be some shrinkage, however this can be mainly mitigated by ensuring all the screws are used in the installation and they are firmly secured into the timber.