Magnic indicates in their advertising that the output of a pair of these is somewhere between 20 and 40 lux
It's a pet peeve of mine when manufacturers use non-standard units in their specs. Lux at what distance? (I'm not asking you. I looked on their site, and it's not specified, and the link to their datasheet results in a "404 Seite nicht gefunden" error.)
As a reference, I just measured the illuminance of a small tail light that seems similar. Its 2 lumen mode measured 9.7 lux at one meter, and its 20 lumen mode measured 76.4 lux at one meter. Keep in mind that these numbers are a very rough approximation, since the relationship between lumens and lux are highly dependent on the shape and efficiency of the reflector.