Home / Retarder Equipment / Two Retarder Relay Box Haugland Two Retarder Relay Box Haugland TERRB3 Two Retarder Relay Box Haugland Enquire about this product SKU: 2151 Category: Retarder Equipment Tag: Haugland Product ID: 2151 Related products Klam Retarder RCU Control Box 18085 NEW Scania Duncan Potentiometer Retarder Unit.