Coverlon Company In-Ground Swimming Pool Covers for Sale and with Free Nationwide Shipping from Family Leisure! In the world of swimming pool protection, nothing compares to this brand This family-owned company has been producing products since 1990 from Branchburg, New Jersey. While being American made is certainly a plus, it's the attention to quality, stability and durability that separates them from their competition. They offer several safety and winter cover products for in-ground swimming pools. Choose between solid green or blue vinyl-coated polyester or mesh polypropylene for your material. It will keep out water, leaves and other debris, while the mesh material is permeable, allowing water to trickle through while keeping the above mentioned undesirables out. The mesh is available in either a Conventional Mesh Material or a Super Dense Mesh Material; both are extremely strong, with the Conventional Mesh offering a thread count of 34 x 22, higher than the industry standard of 34 x 20.