Therabuilt 15" Diameter Seat, with 4.25" Thick Foam. Adjustable from 18 to 23 inches, Very Nice Stool, most of our staff uses them instead of chairs! Very Easy to Assemble, no tools needed. Perfect for use a professional physician stool or massage stool Specifications: Dynamic Load: 250 lbs distributed load Net Weight: 10 lbs Height range: 18" to 23" Padding: 4.25" Semi-firm foam system Upholstry: Durable PVC vinyl upholstering. Therabuilt® is a registered trademark of Clinical Health Services, Inc.