14-19 POLARIS SPORTS570: Polaris Genuine Accessories Lock & Ride Cargo Box Backrest (Black) This backrest provides a rider comfortable and stable back support when a Lock & Ride&#8482; Cargo Box is attached to the rear rack.It is made of ultra-strong steel and durable upholstery and comes pre-assembled.A Lock & Ride&#8482; Backrest (sold separat