I'm sure there was exactly this thread recently. Anyway, what a lot of people said is that there is a HUGE jump in rear light performance from $25 to $35. There are a ton of very good lights in the $25 to $35 range. Unless you absolutely can't afford it, it's well worth spending another few bucks and get something like the Cygolite Hotshot, the PDW Danger Zone or Radbot, and several others, all < $35.
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