I purchased two of your 30 watt pole holder solar panels to help in maintaining the Group 27 battery on my cruising sailboat and they have worked very well in providing a constant daytime charge of just under 14 volts.
As I consume, at most, 24ah daily by being pretty stingy with consumption, the 60 watts of charging power goes a long way towards meeting my power needs.
The panels are mounted on my stern rail and the simple adjustment they provide has made changing the angle of the panels according to the direction and degree of heel VERY easy.
I also appreciate the portability. The panels are dead simple to remove as may be called for in "dicey" anchorages or in the yard.