8-12mm White Dolomite Spar. Ideal uses:Fish friendly – wash prior to useAlpines & rock gardensBorders & bedsEach bag covers approximatelly 0.4 square metrePlease note, when calculating how many bags you will need, a minimum depth of 35mm is recommended.Web Orders: Due to the nature of this product we are unable to send by post or courier.We deliver to locally, we also offer a click and collect service.