They make this laser with the Walther Logo and are the suppliers to Walther America.
This Laser comes as a standard model #30301
or with a light rail built into the bottom of the laser #30303
This company makes a good product..........I have the Laser that sticks out......... and it has worked perfectly for over 1000 rds using hot ammo. The laser lens has retained the original zero. The reason I chose this model is the ability to attach an optional flashlight head. Also this laser has a 40 hour runtime rating. The laser you are interested in has a 3 hour runtime, but is a very compact laser for the Walther.
They also sell a nice tactical combat holster for the Walther Laser equiped handgun.