At 3,400 lumens on full power, the Gloworm eXesSiVe (or Gloworm XSV for short) is the brightest Gloworm light I’ve ever tested.

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It has three Cree LED emitters, arranged laterally in the machined aluminium body and, like all Gloworm lights, these can be swapped out allowing you to customise the beam pattern. A wide and two spot lenses are fitted as standard but to mix things up, spare spot, wide and flood optics are included in the box

The unique feature of the XSV is you can sync it with one of Gloworm’s dedicated helmet lights and, using the included two-button remote, both lights can then be activated together. The syncing process is straightforward too — you just press the button a couple of times and you’re done.

Two light modes are offered – Trail and Commuter. In Trail mode there are four power settings – low, medium and high – and also an emergency dim setting. In Commuter you just get high, low and flashing. Run time is a claimed 1.5hrs in high beam, but I experienced a bit less than that in the recent cold weather.

Gloworm offers several mounting options. I went with the QR plastic 31.8mm bar clamp, but a 35mm clamp option is available, and two tabs on the bottom of the lamp also let you attach it to a Go Pro armature, be that on the bar or your helmet. An extension cable is provided should you want to route it up top.

The XSV hooks up to a 6,800 mAH Lithium Ion battery, which now has a built-in fuel gauge, although with the battery mounted on the frame, it’s not easy to monitor when you’re riding. I’d rather have this readout on the back of the main unit, like on Exposure and Genesis lights. I’m also not a fan of the hard-case battery pack because it doesn’t fit that well against a curved frame tube.

With the stock optics, the Gloworm XSV has an excellent spread of light – you can easily see things in the far distance, but there’s still plenty of light for close-in work, like when picking your way down technical singletrack. On full beam I could really ride fast with this light, just not for that long. I do like the light integration — it’s a neat idea — but to make it really useful I’d like to see run time for both lights displayed up front, rather than tucked away where I can’t see it.