FSA Orbit Xtreme Pro 1.5" External Cup A serious light weight that delivers colossal strength. The FSA Orbit Xtreme Pro 1.5" External Cup headset utilizes industrial sealed cartridge bearings and all-alloy construction to provide reliable strength with minimal weight punishment. Alloy cups press into the headset 20mm to for maximum support and to reduce the risk of head tube wallow. Features: Stack Height 16.5+13.4=29.9mm Weight: 140g 1.5" industrial bearing For 55mm OD head tube 1.5in steerer 20mm headtube insertion Forged and CNC machined alloy cups Industrial cartridge sealed bearing Alloy crown race | FSA Orbit Xtreme Pro 1.5" Headset Black, 1.5"