Add this topper to your mattress for an additional layer of comfort. It's filled with 100% carded wool from Merino sheep and encased in an organic cotton cover. Together, these materials are naturally breathable and temperature regulating as they help to wick away moisture so you have a more restful night's sleep. Filled with 400g/sqm of wool, with a thickness equal to a medium wool duvet Elasticated straps on each corner ensure this topper stays in position Works well with linen bed linen How to care for this mattress topper We don't recommend machine washing your merino wool bedding. The best way to keep them clean, fresh, bacteria and toxin-free and to ensure they last, is to air them in the sunshine on the washing line at least four times a year, preferably at the start of each season. The sunshine sterilises the wool and the cotton and the warmth of the sun will encourage any moisture trapped within the wool to be wicked away. Airing these products also encourages the fibres of the wool to naturally expand back out, ensuring that the pillows and duvets are revitalised and bounce back to life. At first, you may notice the smell of lanolin on your Merino wool bedding. This is a natural oil secreted by sheep that helps soften, protect and waterproof the wool fibres. This wool bedding is not over-processed, so some lanolin remains on the wool. The scent will fade over time but if you have a sensitive smell, we recommend airing your bedding before use.