TRUEGRID PRO PLUS (1.8" Depth) Permeable Pavers, Roads, Parking Lots, Stables (10-pack 40 Sf) Each box contains 10  24 x 24x 1.8 grids covering 40 square feet Over 1million lbs per square foot compression strength. 100% permeable. Detention under surface. No maintenance. Patented system for gravel or grass fill. Made in the USA. Up to 60 year life. Easy installation No staking. No more mud or puddles.