Needing two CR2032 batteries (included), the flying-saucer-esque Redlight II has four LEDs in a semicircle design to give good 180-degree visibility.
The trouble is, with technology moving so fast, the light output appears weak compared to many rear lights currently available, even at this low price. It attaches simply using a rubber O-ring to a range of seatposts and seatstays.
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