Equip your semi to be Ready for the Road Ahead , with the Whiting 96" Roll Up Door Complete Balancer Assembly, a key component to provide your semi with a smooth and reliable spring-operated door assembly. Thanks to its robust design that offsets the weight, this replacement balancer assembly is the ideal product to ensure your roll up door opens and closes with ease. Fashioned with rust and corrosion-resistant metals for extended use in rugged climates and harsh conditions. FleetPride is your First Click in Heavy Duty .