If mortar droppings behind masonry walls block moisture from draining, problems like efflorescence and freeze-thaw cycle damage can arise. Wall Defender from Mortarnet Solutions collects mortar droppings before they can clog weep holes, and the 90% open mesh structure promotes moisture movement and drying. Available in 0.4-, 1-, and 2-inch thicknesses, with 100 linear feet per package, Wall Defender features as much as 54% recycled material. Pricing is set by distributors. mortarnet.com