3 Meter Silicone Hose Kit Set For Engine Bay Dress Up 4Mm 6Mm 8Mm 12Mm Blue P1 for Mazda Miata This is a set of four (4) 3 meter sections of hose. Inner diameter for first hose is 4MM (.157"). Outer diameter is 8MM (.315"). Inner diameter for second hose is 6MM (.236"). Outer diameter is 10MM (.393).