Customized Stress Relievers, Semi-Truck Stress Reliever - Polyurethane, Our stress relievers are made of squeezable polyurethane. Some distortion of the imprint can be expected and ink coverage can vary. Due to the nature of the material, uniformity of the imprint cannot be guaranteed and may break up. Because they are hand made, no two stress relievers are the same. These products are not intended to be toys and should not be given to children or pets. Stress reliever color may vary.. ... #12177 $2.58/each.