The Volvo B9R is a rear-engined coach chassis built by Volvo. It can be built with bodies up to 13m long and a maximum gross weight of 19,000 kg. The B9R is equipped with a rear-mounted Volvo 9.0-litre 6-cylinder diesel engine under the floor, producing 380 bhp (283 kW; 385 PS) and torque of 1,700 N·m (1,254 lb·ft). The Plaxton Panther is built on the B9R chassis and provides 53 seats. The Sunsundegui bodywork provides a 55 seat arrangement.