Standard 1/4″ SS-316 tubing are closed at one end, and have a laser drilled hole diameter.
The standard orifices may be used on 1/4″ fitting and valve components for critical flow orifices, flow restriction, gas/liquid separators, molecular beam masks, particle counters and many other mechanical purposes.
Optically measured holes are not guaranteed to meet a specified flow rate.
Optically Measured Tolerances
Flow Calibrated Tolerances