Internal HS Upper - Orbit Z - 44mm ZS HEADSET TYPE: Threadless Zero Stack STEERER TUBE: Straight 11/8" MATERIAL: Alloy UPPER CUP: 44mm Flush Cup UPPER BEARING: 36° x 45° 11/8" ACB Sealed Bearing 41.0mm OD External HS Upper - Orbit X - 34mm EC HEADSET TYPE: Threadless External Cup STEERER TUBE: Straight 11/8" MATERIAL: Alloy UPPER CUP: 34mm External Cup UPPER BEARING: 36° x 45° 11/8" ACB Sealed Bearing 41.0mm OD Integrated HS Upper - Orbit C - 41.8mm OD HEADSET TYPE: Threadless Integrated STEERER TUBE: Straight 11/8" MATERIAL: Alloy UPPER CUP: N/A UPPER BEARING: 36° x 45° 11/8" ACB Sealed Bearing 41.0mm OD Integrated HS Upper - IS2 - 41mm OD HEADSET TYPE: Threadless Integrated STEERER TUBE: Straight 11/8" MATERIAL: Alloy UPPER CUP: N/A UPPER BEARING: 45° x 45° 11/8" ACB Sealed Bearing 41.8mm OD