Ventura [1] has single speed chains that are
1/2x1/8", but also 1/2x3/32".

If there isn't a marking, can you deduct the
chain size from the width of the chainring
and/or sprocket?

Probably either chain will work, right?

$ echo $(( 1/8.0 ))
0.125
$ echo $(( 3/32.0 ))
0.09375

[1] http://www.ventura-parts.com

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