[Hasegawa, Kokeyama, Kawamura, Akutsu]

The oplev viewport windows listed below were replaced by new ones (Fig. 1- 4):

• [WAS] #0019, #0022 @MCE -> [IS] New #0008, #0016
• [WAS] #0020, #0024 @MCF -> [IS] New #0005, #0006

The new ones use the same glasses numberd in the same as the previous version; each glass is fixed to the flange with an o-ring.

During the work, I found one of the screws fixing the glass to flange was loosen (Fig. 5). Then I found all the screws of all the viewports (at least the ones replaced today) were loosen, so we tighed them up less than 5Nm torque. I'm not sure this torque is sufficient.