Premium Stress Ball Kit (3 Pack) - Hand Massager/Exerciser for Stress Relief, Grip Strength and Joint Pain (3 Resistances) Relieve STRESS and Massage away Hand Pain with simple Squeezing and Rolling. Satisfaction Guaranteed or your Money Back! BUILD STRENGTH: Improve hand, grip and finger strength through easy squeezing and hand therapy movements. DESIGN: Made of durable thermoplastic elastomer (Like Silicone) to handle any grip. No hard plastics and rubber or foam that rips. Reduces any stickiness or residue and easily cleaned with water rinse. FITS snug in palm for hand muscle development. 2.5" x 1.5" (6.35cm x 3.8cm). A little larger than a chicken egg. 3 different RESISTANCE levels (soft, medium and firm) allows you to start light and work up to your desired comfort.