A tail light is an important piece of night-time cycling equipment, while a rear-facing ride-recording camera is good to have in the event of a run-in with a car. Currently on Kickstarter, TOOO Cycling's DVR80 combines both tools in one device.
First of all, there are already other tail light/dashcam combos, most notably Cycliq's Fly6. According to TOOO Cycling, though, its product is brighter, offers a longer recording time, and is less expensive.
More specifically, the DVR80 puts out 80 lumens, it can reportedly record 1080p/30fps footage for up to 9.5 hours per charge of its 2,500-mAh lithium-ion battery, and should ultimately sell for US$193 if it reaches production – Kickstarter pledges start at $179. By contrast, the Fly6 puts out 50 lumens, records for approximately five hours per charge of its 2,000-mAh li-ion battery, and sells for around $230.
Like the Fly6, the DVR80 records its video in a continuous loop, with newer footage constantly overwriting what was previously recorded. When its integrated IMU (inertial measurement unit) detects that a crash has occurred, though, the newest footage is saved to an onboard SD card. That video can then be used in court, to show that the cyclist wasn't at fault – assuming they weren't, that is.
The device is additionally IPX5 waterproof (it can withstand low-pressure water jets from any angle), it can be mounted on aero seatposts via an included adapter, and its Sony IMX323 image sensor is claimed to excel at shooting sharp video in low-light conditions.
That said, the DVR80 definitely is bigger and heavier than the Fly6. While the DVR80 is 165 mm tall (6.5 in) and weighs 90.5 g (3.2 oz), the Fly6 is just 71 mm tall (2.8 in) and tips the scales at 77 g (2.7 oz).
Sources: Kickstarter, TOOO Cycling
Best is to compare to the Fly6 CE model. And it that instance, TOOO Cycling DVR80 offers a much smaller and lighter-weight product with better specs (battery, light, software, mount, after sales)