Donaldson X002277 Informer Restriction Gauge, 1 Pack For more than 50 years, Donaldson has been a leading supplier of exhaust systems, components and accessories for medium- and heavy-duty diesel powered equipment Our innovative products solve complex filtration and exhaust system challenges that improve lives, enhance performance and protect our environment Our exhaust system product line includes everything you need for a wide variety of on- and off-road applications