Our ergonomic grip measures 35mm. Hampton pro-Hex dumbbells are made with a solid steel handle from 15lbs. to 100lbs. They are turned down from 35mm stock, unlike the competition who cast theirs at 25mm. Our competition's are made entirely of cast iron, which increases the chance of the head breaking away from the handle. With Hampton fish tail molding process, safety is critical yet unseen. With a baked enamel finish, the pro-hex dumbbell has the toughest and most durable exterior coating in our industry.