Sigma Mono taillamp (battery)


StVZO approval no: K1031 (non-flashing version only!)
Mass: 40 g (with battery and O-ring).
Size: 46.6 mm width, 46.6 mm height, 24.8 mm thickness.
Light source: 1 red LED.
Mounting method: On the seatpost. You can adjust the angle.
Battery: fixed internal, type?
Construction: Plastic.

Price: ca. € 23,-

Power: ?


I like how it looks, similar to the Stereo, a lot less clunky than the Lightring taillamps...

Beam shots

See the camera settings page for more on the setup and settings to make pictures of the beams of taillamps.

Out of a corner (showing how much light is cast upwards, forwards and to the sides) [ F3.9 & F1.8 ]:

Wallshot (showing the beam pattern):

Visibility from various angles (0°, 45°, 90°, 135°) [ 0.5m, zoom x3, F3.5, ISO80, 1/250s & 1/60s ]:

Comparing taillamps


The optics are pretty good, no blinding of trailing cyclists, the light is distributed very well over a larger area which is the ring around the LED but the LED lights up a bit in the middle too (and not as a point source!). The light at close range can be annoying to some (I asked someone else to judge it too), so better distribution over a bigger surface is still what we need, not a higher intensity. There is a section of light in the beam that is nearly collimated so it gives good long distance visibility.

The rubber cap on the micro-USB port is a bit hard to get off but even more difficult to get back in, but I suppose that means it will be waterproof there :)

The mounting method is by rubber band which Sigma thinks is cool for bike computers and lamps, but in this case I don't mind it as much as with the Stereo (where you want the mount to be fixed on the bike, here you take off the entire thing). The on-off switch is not as good as on the Lightring, but I experienced no key-bounce yet contrary to with the Stereo. As with the Stereo, I feel you need to press it too hard.

The battery, not sure what type, I've not opened it up yet.


The Mono has a good total concept (rechargeable battery with micro-USB port) coupled with smaller mass and much smaller size than the battery version of the Lightring and it looks nicer than the Lightring. Visibility is good, it doesn't annoy trailing traffic (some people won't like it nearby, too bright), the mount with the rubber rings is OK for this lamp (for the Stereo it's stupid because you leave its mount on the bike).

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