Sir sponges are manufactured with pure cellulose (a wood derivative) which has the ability to absorb many times its weight in water. All sponges are RoHS compliant and meet ANSI/J-STD-001B standards for low sulphur content and fine porosity. Also resistant to abrasion and tearing forces that occur during the tip wiping process, a single pass of the solder tip over the sponge easily removes all of the excess solder and residue. - The sponges are designed specifically for the electronics industry and clean solder tips quickly and efficiently, keeping contaminates off the tip and out of the solder connections. The compressed sponge structure is designed to expand when wet and retain water for long periods of time.