SMC Networks PFMC7501 Operation Manual page 17

Direct mounting
For direct mounting use M3 screws (2 pcs.) or equivalent.
Screws are prepared by customer.
Refer to the dimension drawing (page 71) for the diameter and depth of the mounting screw holes.
Tightening torque is 0.5 to 0.7 Nm.
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No.PF※※-OMS0002-B