All product sizes and weights are in the information files
The classic brass Ball & Ring apparatus to prove and demonstrate the effects of heating a metal.
If the ring is chilled in ice, the ball cannot pass through the ring. If the ball is heated, it cannot pass through the ring. A chain joins the ball to the ring so they cannot become separated.
The IEC item is carefully machined and matched for size so that the experiment works. Many imported items are poorly made and have no chance of working.