10in Polyester or Nylon Cloth Squares are specially designed to fit non-metallic or brass two-part frames. The square has a resilient material embedded in the mesh in a circular shape, acting as a sealing gasket. Opening sizes are equivalent to ASTM E11 sizes but do not meet tolerance requirements.
Polyester is recommended for most applications because it resists abrasion, acids, and most alkalis up to a pH of 9-10 while maintaining very strong wet stability. Nylon has excellent abrasion resistance, high tensile strength, and resists higher pH levels but tends to stretch in the water.