ACB 4545 1125T SS - 1-1/8" 440C stainless steel Angular Contact Headset bearing (30.15mm x 41mm x 7mm: 45x45deg)
Angular-contact headset bearing featuring 440C stainless steel balls and races for superior corrosion protection.
This size bearing is also known in the bike Industry by part number:
MH-P03H7