Permeable Ground Grid and Grass Pavers is an interlocking porous paving system designed to reinforce the groun Perfect for carparks, driveways, paths, patios and muddy areas 20 in. × 20 in. × 1.8 in. Pack of 4 pieces. Eco-friendly car park solution with natural drainage; Suitable for 44 tonnes vehicles Improves storm water management as part of sustainable urban drainage (SUDS) initiatives Prevent mud, puddles,rutted grass, gravel migration, Easy installation, No tools or staking. Permeable Ground Grid is an interlocking porous paving system designed to reinforce the groun Perfect for carparks, driveways, paths, patios and muddy areas.