25mm - 1 inch car rubber EPDM hose is a flexible hose that is typically used in automotive applications as a heater hose. The hose has an inner diameter of 1 inch, making it suitable for use in vehicles with a larger than average heater system. EPDM stands for ethylene propylene diene monomer, which is a type of synthetic rubber that is commonly used in automotive hoses because it is resistant to heat, ozone, and chemicals. The rubber EPDM material of the hose makes it flexible and durable, able to withstand the high temperatures and pressures present in a vehicle's cooling system. EPDM hoses are commonly used in both automotive and industrial applications.