The most reasonably priced component used on the Gs400 1978 (c) (e01 E02 E04 E17 E18 E21 E22 E24 E25 E30 E34 E39) Brake Hose is the Washer.
The most expensive part in this assembly is the Hose,front Brake.
This BRAKE HOSE assembly utilises four Washer(s) - the highest specified component.