Anonymous ID: 625c4a Sept. 19, 2020, 10:45 p.m. No.10717779   🗄️.is 🔗kun

It's when in a submarine, they turn the lights red before coming up to periscope depth in order for eyes to adjust to get ready for the light adjustment. Using the periscope often meant targeting and preparing to fire on an enemy vessel

>>10717044