Sensors in automated equipment depend on mechanical stability around them. A sleeve may protect the sensor, locate it, carry heat away or control spacing in a compact assembly.
The RFQ should make the sleeve's function clear. If the part controls sensor position, concentricity and end-face quality may matter. If the part affects heat transfer, material and surface condition may matter more.
Weeda Precision produces sensor sleeves and small turned components to drawing. Buyers get better results when they share the sensor type, mating housing and the dimension that controls final alignment.