Aid and Trade

Retail Price: $8.95 Wholesale Price:     $6.95 Your Profit: $2.00

This unit demonstrates the expansion of metal when heated and its contraction when cooled. Hen either the ball or ring is heated, the ball will not pass through the ring but when cooled, the ball passes through the ring easily. The ball and ring are mounted to an insulated wooden handle to protect your hands from heat.