w/ help by Y. Inoue: 2 pieces of oplev viewport windows (ICF70) for EYA were installed; the serial numbers of them are S/N005 for +X side and 006 for -X side.

M6x35 hex socket-head cap screws from CAL's screw set (thorlabs one) were used to fix the viewports, as the original sets (screws, washers, and nuts) are lost anywhere. In the usual case of this kind of viewport installing, for each individual screw, a washer is inserted at the cap-side of the screw, and another washer at the nut side, but as shown in the attached figures, the flange assembly does not have enough spaces (recesses) around the cap side for washers, so no washers were used for the cap side.

The torque: started with 7Nm, then 10Nm.

Note: screws with thinner cap heads were accompanying with the ICF70 viewport windows thanks to the retailer, but we don't need to stick to use the special screws.