Chem-Wik rosin is especially designed for today's heat sensitive electronic components. The lighter mass, pure copper braid construction allows for better thermal conductivity, even at low temperatures. - Chem-Wik rosin responds as much as 50% faster than conventional desoldering braids. This design minimizes overheating and requires less "contact" pressure for greater operator control. All sizes are coated with a Type "R" organic flux system.