Lower +/-0.75 degree 1.5" HS02-A (angleset) headset cup without pre-installed bearing.
The cup size is specific to the compatible frame size. Check your bicycle´s technical manual to know what cup size corresponds to your frame size.
100mm Headtube: Rallon S
110mm Headtube: Rallon M
120mm Headtube: Rallon L, XL