I bought this to go with a K&M light (K&M 12247 T-Model LED FlexLight)
I found that the light goes through batteries very quickly, so this power supply is very useful.
The 3m long cable is very useful, as there isn't always a power outlet close to where I need it.
The only small negative for me is that Thomann don't stock it with a UK plug, but thats not a big deal.
For the price I would recommend it for all K&M lights.