The personal ray shields that saw action during the last stage of the Big Game on the Wheel were treated with refractory coating. While this material wasn't strong enough to deflect standard blaster fire, it proved effective at bouncing back the less intense energy beams of the needle rays utilized in the Big Game. A reflected blast retained almost all of its original power, remaining lethal. Using a ray shield concealed beneath his clothing, and coated with this refractory material, Han Solo successfully simulated his demise from a needle ray attack.