This is the bush that fits inside the radius arm (hockey stick) at the axle end.
This bush fits the rear arms at the axle end only. Therefore two are required per arm, which means four are required for the entire car.
This is for a single bush.
This is a bush made to OEM specification so it has the slots moulded into the bush. These slots are designed to be aligned into a specific position as shown in both the additional diagram and the photographs attached.
This is the key difference between this and "Polybush" offerings. Suzuki put the slots into for a specfic reason, giving extra movement in a set direction. This is probably for ride comfort. Polybush solutions do not have this and are often of firmer material so the whole ride can suffer.
Please note: these bushes require pressing into the arms.