This part of the number specifies a 0.6mm stacking height, 10 signal contacts, a dual-row plug, and a 0.35mm contact pitch. The suffix (51) indicates the packaging, which is tape and reel. The BM28 series is a Hirose Electric FPC-to-Board connector series with a 0.35mm pitch and 0.6mm stacking height, supporting up to 5A.