Lower Radiator Hose

The Lower Radiator Hose carries coolant from the radiator outlet to the thermostat housing.

Upgrades

The stock radiator hose is thick multi-ply rubber. Some feel that, despite the fact that the cooling system is pressurized, the rubber can soften and collapse under suction caused by the water pump. For this reason, silicone lower radiator hoses are often not recommended unless they are spiral wound (which is rare).
Instead, a good alternative is an aluminum hard pipe with silicone elbows.