The two hoses to the left of the thermostat are cooling water hoses, and are just standard size hoses cut to fit (but the hose by the meter from the local MB dealer). The bottom hose is not cooling water, but air inlet. There has been some mention on the site about this special hose marking (which is not available) I think it is the same size as the heater hose. The fourth one is going to the head (from the heater) and depending on the car, may or may not be a special "formed"hose. On my 250 SL it is just a piece of hose cut to fit.