The red knob (spare part code 3.008.100) is the control handwheel of the water softener tap used on softening modules and professional warewashing equipment. It is the part you grip to open and close the water flow through the tap, acting on the stem of the valve head underneath.

The red colour conventionally identifies the hot or supply water line, in line with the same series of tap knobs that includes the hot red version (code 3.008.313) and the cold blue version (code 3.008.314): choosing the correct colour makes the control immediately recognisable on the machine.

This is a wear part: over time the plastic knob can crack, split or spin freely on the stem, or fade and lose its grip. When that happens the tap becomes difficult or impossible to operate, and only the knob needs replacing, without touching the rest of the tap.

Practical tip: before purchasing, check that the fitting type and the knob seat match those of the tap in use, comparing the part to be replaced with this spare.