These slip inside current Gates hose to reduce inside diameters. Gives maximum coverage with minimum hose inventory. Makes it possible to adjust inside diameters of larger hoses for emergency replacements. These are quality rubber constructed reducers which assure maximum dependability, with no leakage. They fit all Green Stripe II straight or Green Stripe Vulco-Flex hoses. Caution: These reducers are recommended for coolant and air applications only.