Thompson's Advanced Patio and Block Paving Cleaner 5 Litres Clear, is a water based cleaner for blocks and paving. The Thompson's cleaner comes with a coverage of 4m2/l and a drying time of 30 minutes. The paving cleaner removes dirt, moss, mould and algae. The cleaner is made of 2 percentage of benzalkonium chloride. The product is used on paving slabs, block paving, flag stones, concrete and red bricks.