A seatpost with a light built into it might seem a slightly strange idea, but it means you won’t be able to forget your light and there's no chance of it falling off or rocking downwards.
However, it also has its drawbacks. It doesn’t sit at the correct angle on most bikes and ends up pointing down too much, so most drivers behind are never going to see it at its brightest.
Run-time in flashing mode was eight hours less than claimed at 52 hours, and to change the batteries you need a small cross-head screwdriver.
The seatpost itself is a good quality unit from Kalloy, with the tubing suitably thick to take into account the large slot machined into it for the light.
Available in 27.2mm diameter only, with an overall length of 350mm and a usable length of 265mm, it tips in at a pretty hefty 387g with the two AAA batteries installed.