I have a 1 1/8 size fork with a FSA Orbit MX 1-1/8Inches Threadless MTB Road Headset with a fixed piece on the top and bottom of the headpiece. I don't know
FSA - Orbit MX 1 1/8 Headset : Bike Parts | State Bicycle Co.
FSA Orbit MX Headset 1 1/8
FSA Orbit MX Headset user reviews : 4.3 out of 5 - 6 reviews - mtbr.com
FSA Headset Bearing Sealed for Orbit XLII
BLUE FSA ORBIT MX 1 1/8” HEADSET SEALED BEARINGS LIGHTWEIGHT 69% OFF RRP £54.99