The center pin will provide: Proper height for pre-wound or “L” type bobbins. Smooth and consistent thread flow through the tension. Proper balance of bobbins. - Babylock Sofia BL137A & BL137A-2, Accomplish BL520B, Aerial BLAE, Aria BLAR, Destiny BLDY & BLDY2, Ellegante BLG & BLG3, Ellageo BLL, Ellageo Plus BLL2, Accord BLMCC, Journey BLJY, Meridian BLMA, Adventura BLMAV & BLMAV2, Verve BLMVR, BLMR, Esante BLN, Spirit BLPY, Ellure BLR & BLR2, Ellure Plus BLR3, Solaris BLSA, Ellisimo BLSO, Ellisimo Gold 2 BLSOG2, Altair BLTA, Unity BLTY - Brother JX1710, NV1000, NV2500D, NV2800D, NV4000, NV4000D, NV4500D, NV4750D, SE1800 - Alternative number XC8450051, XF5048001