SEESEE.U 34/44/44-55/44-56mm 1-1/8 Threadless Double Bearings Bike Headset, Internal/External Sealed Bicycle Headsets for Road, Fit Straight Tapered Head Frame Star Nut Top Cap : Amazon.co.uk: Sports & Outdoors
Nikou Bike Headset - CNC ZS44/ZS56 Aluminium Alloy Bike Double Purpose External Taper Headset Bearing corrosion-resistant for Bicycle : Amazon.co.uk: Sports & Outdoors
Ztto Cnc Zs44/zs56 Aluminium Alloy Bike Double Purpose External Taper Headset Bearing For Bicycle | Fruugo UK
Cane Creek S3 External Cup Headset For 1 1/8 Inch Forks TotalCycling.com
Road Bike ZS44/ZS56 External Cone Tube Tapered Heads Bowl Set Bicycle Headset | eBay
Dan's bike stuff: Headsets and associated standards
Forty (40-Series) Headset | Cane Creek Cycling Components
Thoughts on Tapered forks on Straight Frames (external headset) | Mountain Bike Reviews Forum