Magnetic pattern recognition sensors are composed of a wear-resistant case (or cap/cover), magnetoresistive elements, permanent magnet, terminal pins, and holder components that bind them together.

With the BS05N1 and BS05C1 types, the operating pole of the permanent magnet is the S pole. With other types of sensors, the operating pole is the N pole. The positional relationships between the magnet and the elements, and between the elements and the case are accurately determined with the plastic holder.