The openQCM window cell has two holes for tubing connection in application with liquids. If you look closely at openQCM cell window, you can see that the holes are slightly different. One of them is larger than the other. The dimensions of the of the inlet and outlet holes are the following:

• Inlet dimensions – larger hole
  ID = 0.9 mm
  OD = 1.8 mm
• Outlet dimensions – smaller hole
  ID = 0.6 mm
  OD = 1.6 mm

The precision machining is mainly due to the CNC milling machine that we used for making the window cell.

openQCM window cell inlet – outlet holes