size 1 1/8 in. (28.6 mm) stack height +1.0 mm to Cover Height top stack height 17.0 mm bottom stack height 10.3 mm material Premium Headset Alloy 7075 T-6 weight 67.0 g - Tall/60.6 g - Short (excl. spacers and preload assembly) top bearing Split-Lip Stainless Steel bottom bearing Split-Lip Stainless Steel