FSA High Grade Bearing ACB518K MR127 St TH-073E 1 1/2'' 1.5

ACB518K, MR110, MR127, TH-073E MR110, ACB518K, TK518B. 1 x 1.5" Lower Bearing (TH073) for an FSA Orbit (No.57) Headset. You will also need an upper bearing which is PO3K / TH873E / MR122. ZS56 BOTTOM HEADSET BEARING.