Back-Up Barz Bicycle Handle Bar Bike Attachment for Upright Position Back-Up Barz consists of a high-strength, lightweight (14 oz.) alloy. Handlebar Clamp Diameter: 26.0 mm to 31.8mm User can customize bar positioning to their needs Medical studies prove changing riding positions relieve pressure on back, shoulders, neck and arms Most injuries cyclists suffer are due to traditional handlebars on touring and racing bikes