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Sigma Nugget Flash Rear Light



Very good little commuter light: no unnecessary modes, a quick recharge, two tool-free mounts and not overpriced

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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Sigma's Nugget Flash rear light has changed very little over recent years and it's easy to see why: it's a versatile, easy-to-use design that ticks all the boxes for a commuter light. Stick on a competitive price tag and it's a winner all round.

'Nugget' is a perfect description of the light: a compact (approximately 4 x 3 cm) unit with a tapered depth that results in approaching traffic getting the full force of its beam. It's pretty small in comparison with many lights out there, but the 0.5 watt LED is bright enough to be seen from roughly the 400m that Sigma claims. The Nugget features a Fresnel lens – a ring-shaped design that helps to distribute the light evenly and so maximise brightness; the 220-degree angle will not be beaten by many other lights of this size or price.

Battery and charging

The integrated lithium-ion battery recharged inside the stated two hours and an indicator light switches from red to white when this has been done. Once charged, the light I tested ran for just over the stated times in each of the three modes: on high power a little over 3 hours, on high flashing over 8 hours, and on standard 7 hours 15 minutes. These are pretty decent run-times for a short recharge time. Certainly sufficient for a few commutes for most people.

A tiny indicator light on the lens face turns red when the battery is running low. This wasn't when at 30% power remaining as claimed, it was closer to 20%, but hardly an issue. Detecting this light means you have to look straight at the LED – not ideal. I resorted to covering the bulk of the lens with my hand in order to look.

One click cycles you through the modes: high-standard-flashing-off. There's no mode memory function and you have to go through 'off' to get back to high. The pimple switch is easy to locate and operate, even in gloves. Bulky winter ones were an issue and it was certainly quicker to just take them off.


The Nugget comes with two different mounts: an adjustable silicone bike one and a plastic clip. The bike one fits snuggly to the Nugget and a large curved face of silicone comes into contact with the frame or seatpost, while a strap wraps around with various attachment openings for 24-36mm tubing. Forget aero posts though – the mounting interface is designed specifically for cylindrical tubing. It's a perfect fit on a seatpost, and could easily be mistaken for an integral part of the bike – not a bad thing to deter opportune light thieving buggers.

Sigma Nugget Flash Rear Light - side.jpg

A decent bit of force attaches the alternative mount to the back of the Nugget and transforms it into a tidy cuboid of light that can clip onto a whole range of things: bag, belt, head torch strap... choose whatever you want. Unlike the bike mount backing, the clip needs a twist of a coin to remove it, there is no chance it's coming off any other way.

Rated to IPX4, the Nugget withstands showers and spray. Sigma doesn't claim that it is fully waterproof but it has been fine during recent seasonal showers and downpours.

> Buyer's Guide: 14 of the best rear lights for cycling

The Nugget makes a great light for commuters. It is bright enough to be used on its own, though most cyclists tend to have at least two rear light these days. The wide angle makes it ideal for riding in traffic.

Overall it's a decent investment: a tool-free mount, decent recharge and run-times, no more modes than needed, all with a reasonable price tag. You can spend less – the Moon Alcor that Neil tested is £15.99, with five modes, a mode memory function, and between 4 and 80 hours' run-times – but the Nugget's simplicity really appeals.


Very good little commuter light: no unnecessary modes, a quick recharge, two tool-free mounts and not overpriced test report

Make and model: Sigma Nugget Flash Rear Light

Size tested: 1/2 watt high-power LED

Tell us what the light is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Sigma says: 'The SIGMA NUGGET FLASH is designed for high traffic roads where safety is top priority. This powerful light provides excellent visibility up to 400 meters. Its small size fits perfectly on all bikes, and the belt clip allows you to use it hiking, walking, running, and more.'

Tell us some more about the technical aspects of the light?

Sigma lists:

Uses a 1/2 watt high-power LED and SIGMA's new FRESNEL lens to provide more than 220˚ of lateral visibility.

Powered by a USB (micro) rechargeable lithium ion battery, cable included.

39mm x 28mm lens face and a tapered depth from 25mm to 15mm.

Water resistant- rated to IPX4 standard.

Rate the light for quality of construction:

Very tidy little unit.

Rate the light for design and ease of use. How simple was the light to use?

Ridiculously simple. The first time I attached the clip mount I was a little nervous about applying the force necessary to clip it onto the light but I needn't have been – it's solid!

Rate the light for the design and usability of the clamping system/s

Tool-free and idiot-proof. Tapered profile is spot on for mounting onto a seatpost.

Rate the light for waterproofing. How did it stand up to the elements?
Rate the light for battery life. How long did it last? How long did it take to recharge?

Claimed 2hr recharge time. Claimed 3 hours on high power mode, 7 hours on standard mode and 8 hours on flashing. All were pretty accurate.

Rate the light for performance:

Great – it's visible from the claimed 400m and has a decent angle on it too.

Rate the light for durability:

Survived several drop tests!

Rate the light for weight:

One of the lightest commuting lights out there, so claims Sigma. At 32g with mount it's negligible really.

Rate the light for value:

Tell us how the light performed overall when used for its designed purpose

Spot on.

Tell us what you particularly liked about the light

Tapered profile to angle lens faces directly at approaching traffic.

Option to clip it onto a bag or item of clothing.

No excessive modes: it flashes or it doesn't, it's super-bright or it's 'enough'.

Tell us what you particularly disliked about the light


Did you enjoy using the light? Yes

Would you consider buying the light? Yes

Would you recommend the light to a friend? Yes

Use this box to explain your score

It does everything that a commuter light should for a competitive price: it's very good.

Overall rating: 8/10

About the tester

Age: 37  Height: 173cm  Weight: 64kg

I usually ride: Road  My best bike is: Carbon road

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: commuting, touring, club rides, general fitness riding, getting to grips with off roading too!

Emma’s first encounters with a road bike were in between swimming and running. Soon after competing for GB in the World Age Group Triathlon Championships in Edmonton in 2001 she saw the light and decided to focus on cycling. 

After a couple of half decent UK road seasons racing for Leisure Lakes, she went out to Belgium to sample the racing there and spent two years with Lotto-Belisol Ladies team, racing alongside the likes of Sara Carrigan, Grace Verbeke, Rochelle Gilmore and Lizzie Deignan. Emma moved from Lotto-Belisol to Dutch team Redsun, then a new Belgian team of primarily developing riders, where there was less pressure, an opportunity to share her experience and help build a whole new team; a nice way to spend her final years of professional racing. 

Since retiring Emma has returned to teaching. When not coercing kids to do maths, she is invariably out on two wheels. In addition to the daily commute, Emma still enjoys getting out on her road bike and having her legs ripped off on the local club rides and chain gangs. She has also developed an addiction to touring, with destinations including Iceland, Georgia and Albania, to mention just a few. There have also been rare sightings of Emma off-road on a mountain bike…

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