The original is a plastic tube.
I used 3/8" (9.5mm) Power Steering Return Hose on mine; made by Thermoid. No Clamps needed.

I replaced the original Plastic tube because I want to route the Hose more over the Fender Well and because the Hose is more flexiable I am less likely to break the Plastic Nipples off.

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84 300D, 82 Volvo 244Gl Diesel