Trek E2 FSA Headset Lower / Upper Bearing 36-Degree 51 mm x 40 mm x 6.5 mm Ships within Australia In stock. Available via Click and Collect or Buy Online Share Loading Facebook Like button... Trek E2 FSA Headset Lower / Upper Bearing 36-Degree 51 mm x 40 mm x 6.5 mm Ships within Australia In stock. Available via Click and Collect or Buy Online Share Loading Facebook Like button...