Radiator, heater and vacuum hose is an important part of most engines, but it's not included in most kits. This coolant hose is customed made to solve that solution. Featuring a semi flat finish and a core that holds it's shape when formed, it's easy to add to any model. The dia. is .025. This hose represents a 5/8 inch hose in full scale when used on a 1:24 scale model. 5/16 inch hose when used on a 1/16 Scale Model, 3/8 inch hose when used on a 1/12 scale model, and 1 1/4 inch hose when used on a 1:43 scale model.