Thompson's Patio and Block Paving Anti Slip Additive provides extra grip for your patio and block paving when used with Satin or Wet Look Patio and Block Paving Seals. This additive is quick and easy to use, leaving an invisible anti-slip finish suitable for all block paving, flag stones, granite, limestone, and sandstone. Preparation: This Anti Slip Additive should be used in conjunction with your chosen finish of Thompson's Patio & Block Paving Seal - Satin or Wet Look (this should NOT be used with Natural Finish). Prepare the surface as directed on the Patio & Block Paving Seal pack. For Satin Finishes: Apply two coats of Patio & Block Paving Seal prior to applying Anti Slip. For Wet Look Finishes: Apply one coat of Patio & Block Paving Seal prior to applying Anti Slip. Make sure the seal is fully dry before continuing. Application: A 200g sachet of additive is mixed into the seal before application.