Screw Size for mounting Fan to Ventilation Housing

[TMeeks]

We have a number of Geeetech printers in our print lab. We had to make a move while one of the A10 printers was undergoing maintenance and the screws used to mount the fan to the ventilation housing on the A10 were lost.

Going by our other A10's and A20's, The screws appear to be 2 different lengths of M1.8 screws; but, we need to be precise as to the thread size. What are the specifications for these screws.

Thanks,

TMeeks