Acliff’s all element stable - Carbon, Titanium, Aluminium, Steel

How very dare you!
Its just the headset bearing cover. It used to be a tall Ritchey WCS integrated canti hanger, but changed it to the only bearing cover that would fit (another WCS one).

I've got spare -17 stems, but wanted -12 to get the stem to match the line of the toptube mostly.