I am with Work101 on this HiTen at its finest. It could be some type of Maganese but HITen is my guess. I am not certain of the year either but I believe shipmano was fooling with Positron (and torturing mechanics everywhere) as early as '76 or so.
I don't use mine much but I like it. It also make a great bike to lend to one of the other girls in the building.
PS the frnder chainguard and tool kit have since been reinstalled.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk