Hearing loss varies from person to person so we understand you will want to test One yourself. That's why we offer a 30-day money-back guarantee, to enable you to thoroughly test the stethoscope, work with your audiologist, and experiment in a clinical setting. If it doesn't work for you, you can return it within that time frame for a full refund, no questions asked. Most customers who try The Thinklabs One keep it. Visit our Online Store to purchase.