1.1/8 Upper to 1.5 bottom;For differential OD headtube;For tapered 50mm/61mm OD headtube

• Gravity SX No 55-1 Mountain Bike Headset - Black, 1.1/8-Inch
• 1.1/8-Inch
• Black

Gravity SX No 55-1 Mountain Bike Headset - Black, 1.1/8-InchGravity