Craig`s picture shows the Version 1.0 AAA, the first to be released to the public which was only a small step on from the original hand-made prototypes. Version 2.0 came soon after and was a more refined product. It also had a "gasket" sealing the head, but this one was more of a square-profile o-ring design. The original V1.0 gasket suffered problems with tearing and bunching up, and wasn`t very effective. The flat gasket of V2.0 wasn`t too good either, so the next revision (2.1) and onwards went back to the traditional round-profile o-ring as featured on the very first prototypes.
Early red LEDs used in Arc AAAs were Toshiba parts, with a fairly narrow, somewhat diamond-shaped beam. I forget what the later ones were, but they are much brighter with a wide, smooth spot, and were originally purchased from Photon makers LRI. As far as I know, Nichia have never sold any 5mm round red LEDs. The handful of red parts they do sell are suposedly repackaged dies from another source, intended to match the blue and green ones they make themselves (for colour video screens, etc).
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