There are two versions of this part. This is part number KH124. The end cap is 10mm deep and has approx 10 threads.
Bicycle roof mount for Cannondale Lefty Fork series, front fork bracket is specially designed for Cannondale Lefty Fork series, compatible with models 1.0, 2.0, 3.0, Lefty Ocho, Lefty Oliver
Cannondale Lefty Fork
HollowGram Cannondale Lefty Ocho Front Wheel 29" – Superlight Carbon Tubeless
Cannondale Lefty 29er Fork + Front Wheel/Hub–Scalpel Carbon –2013/2014 – PBR/XLR
VANICE M8 x 18mm Bicycle Bottom Bracket Flanged Axle Bolt, 8mm Crank Bolts Parts for Mountain Bike Road Bike MTB
E-Bike Hub Motor Nuts Bike Safety Washers Electric Bicycle Wheel Lock Nuts Motor Axle Bolt Screw Full Set (M14 Shaft)