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Message: <blockquote data-quote="Kevin Conville" data-source="post: 1755244" data-attributes="member: 63161">Do you have a photo of it popped up?I don't understand the question. In the photo, the top cap is "popped up" in the ready-to-adjust-the-diopter position. This is why the red O-ring is exposed.Did they remove this requirement in the HD?I don't know. Off the top of my head I can't vision how else to keep water and dust from being trapped inside the area where the two focus wheels meet without an O-ring. It's a pretty tried and true design, as Leica Trinovids used the same setup.Regarding maintaining waterproofness... It's a bit of a misnomer to characterize the function of the O-ring this way as it is there to keep unwanted things out of the focus mechanism. Obviously the body of the bin is sealed independently at the focus wheel axles.</blockquote>