• 1-1/8", Retainer bearings • For 50mm OD Head Tube • 1-1/8" steerer • Alloy custom top cover • Ø5/32" x 20 retainer bearings • Stack Height 5.2+3.7=8.9mm • Weight - 93 g Bicycle Parts Parts Headset HS NO.10 0.1 inch (2.5 mm) alloy 1-1/8