New Genuine Polaris ATV Accessories / Lock and Ride Cargo Box Backrest / 2005 through 2008 Sportsman / pt # 2875548 This backrest provides a rider comfortable and stable back support when a Lock & Ride Cargo Box (# 2875176  sold separately) is attached to the rear rack. It is made of ultra-strong steel and durable upholstery and comes pre-assembled.