It is thin-walled unreinforced silicone tubing for vacuum lines, breathers and signal lines - boost gauge feeds, wastegate and solenoid signal lines, carburettor and manifold vacuum takeoffs, crankcase breathers, and general small-bore pneumatic and laboratory work. It is chosen for heat resistance and long life rather than for pressure capability.

Thirty size combinations from 3mm x 7mm up to 10mm x 16mm - the first figure is the internal diameter and the second the outside diameter, so you can pick the wall thickness that suits. Lengths run from 1 metre up to a 30 metre full coil, in blue, red, black and clear. Order by internal diameter to match the spigot it pushes onto.

It is VMQ silicone rated from -60C to +180C with short peaks above that. That is far beyond what the rubber or plastic vacuum tubing fitted as standard to most vehicles will manage, which is why original vacuum lines go hard and split near the manifold while silicone stays pliable. It also stays flexible in the cold rather than becoming brittle.

No. This is standard VMQ silicone, which swells and degrades in contact with petrol, diesel and oil. Be particularly careful with breather lines - a crankcase breather carries oil mist and will destroy plain silicone over time. For anything carrying hydrocarbons use our fluorosilicone-lined hose, which is made for exactly that job.

For normal manifold vacuum and signal-line duty in the sizes offered, no - the wall thickness is chosen to hold its shape. But it is not a reinforced hose, so do not use it on the suction side of a pump, under strong sustained vacuum, or in large diameters where an unreinforced wall will draw shut. For those, use a hose with a wire helix.

For low-pressure signal lines to a gauge or solenoid it is fine. It is not a pressure hose and should not be used for charge air, coolant under pressure, or anything where a failure matters. If a line is carrying boost rather than merely sensing it, use reinforced silicone. Unreinforced tubing will balloon and eventually split under sustained pressure.