Valutek's 23lb letter size cleanroom paper is specially formulated with cellulose fiber, surrounded and bonded by a polymer impregnated substrate. This special formulation minimizes particulate and ink smearing and provides the paper with high tear and tensile strength, ultra low levels of particle and extractable counts. All Valutek cleanroom papers are tested and manufactured in ISO compliant facilities under Valutek inspection and strict process control to ensure Valutek quality standard and product specifications.