A mighty reusable sanitary pad for your very heavy days, measuring 13.5" and 3.5" at the gusset. This pad is one of the thickest we make, with four inner layers of organic cotton fleece as well as the top layer of velour. The Slim Mega pad also has an inner layer of waterproof PUL, (the wool pad does not - this is a simple all organic, all natural pad with an organic black wool backing). The cotton backing option is our black organic cotton jersey, which is a lightweight as well as vegan and delightful pad. The double poppers prevent sideways slippage. Lovely and snuggly, this pad will stay soft wash after wash even without tumbling. Machine washable up to 60'.