This Stone & Concrete Shape Stress Relief Toy Measures 2.48 Inch in Diameter & is Made From Dense, Slow Rebound Polyurethane Foam Rubber with a Textured Surface That Mimics Real Rock & Cement. the Material is Non Toxic, Odorless, & Durable, Offering a Firm Yet Squeezable Feel with Subtle Grain Patterns & Irregular Edges Achieved Through a Compression Molding Process. Its Primary Function is to Reduce Anxiety, Release Tension, & Provide Hand Exercise Through Repetitive Squeezing. the Compact Size Fits Neatly in a Palm or Pocket, Making It Ideal for Office Desks, Home Use, Travel, or Construction Themed Stress Management. Silent & Mess Free, It Returns to Its Original Shape After Each Squeeze Without Deforming. No Batteries Required.