Product Details: The OTR Type 18 2.5" Standard Stroke Air Disc Service Brake Chamber ensures Expertise Built In™, containing the required high tensile strength and innovation needed for the brake safety of your semi truck. This OTR service chamber boasts high quality material to not only meet, but also exceed OEM requirements by thoroughly transforming energy from compressed air to apply the right amount of force to your brakes. FleetPride is your First Click in Heavy Duty®.