WEmake Lead Free Solder Science Kit with 5' Roll and 0.031" (3 Pack) A must have for any self respecting Do-It-Yourselfer LEAD FREE Solder - 99.3% tin, 0.7% copper 0.031 inch Rosin Core Solder for any application 3 pack - 5 foot roll in storage tube Elenco supplies Universities and High Schools with quality educational kits and materials