This German bike light looks much like a Maglite, with a torch-style shape and a file-patterned aluminium body.
The lamp itself is well made and burn time is 'up to 50 hours' with three AAA batteries. What's most interesting about it is the lens: a cam lever on the top brings the lens closer to the 1.25 watt LED, turning the spotlight, by degrees, to a flood.
For riding on unlit lanes, half open seemed best, yielding a long ellipse of light with enough punch to ride at pace. Under streetlights, where the white light doesn't seem so bright, spot was better.
The 'Duplex' part of the name refers to its 'second function': a torch. In truth, you could say any battery lamp is also a torch, and this one is more of a torch that doubles as a bike light rather than the other way about.
The U-shaped nylon handlebar bracket looks a bit like an afterthought: it holds the torch by interference fit rather than a cleat or ball joint (like USE's excellent Joystick light), and this could get worn with use.