String Mop Heads Replacement Washable & Reusable 75% Cotton + 25% Synthetic Rayon Blend offer Higher Absorbency and Strength. Sturdy Sewing Neat Lines, Firmly Fixed Mop Head, Good for Long-Term Use. Scratch Free, Safe for all Hard Floor Surface. Long-lasting fibres allows mop head to be laundered many times giving it a longer service life.