Heat Pack 8″x8″

Description

This hand warmer contains a super saturated solution of water and sodium acetate. Snapping the metal disc creates a chain reaction, causing the solution to crystallize. The crystallization process gives off heat. The heat packs can be recharged back to the liquid state by being boiled in water for 10-15 minutes and allowed to slowly cool. • Comes with a Teacher’s Guide • 8″ (200 mm) L x 8″ (200 mm) W