Custom Stress Relievers, Donut - Stress Reliever - Polyurethane, Donut shape stress reliever, 3 1/2" x 3 1/2" x 1". Due to their handcrafted nature, stress ball sizes, colors and textures may vary. Factory cannot guarantee consistent imprints or PMS matches. Material: Polyurethane. ... #LFD-DN07 $2.29/each.