Good product with small drawbacks. 3

There are two main advantages that I want to emphasize here:

1. Two ports, one for "pumping up", another for "pumping" of the air.
A larger object is so much faster back space saving storage, than doing it laboriously by pressure relief valves (if applicable) must be emptied manually.

2. The known double-chamber make it that the air is directed at every movement in the object to be inflated. While one chamber discharged into the valve, is thus pressed out, the other chamber sucks at the same time filled with air and is already ready to be passed into the valve. This saves time and also power.

Small defects and resulting options:

The pump is made of hard plastic, that is not very stable, it acts when pumping a little "unstable", but worked up to a short defect perfectly. This defect could by screw and manual repair of the items will be adjusted relatively easily. On the beach, and without tools.

However, I found the state of the pump as a non-ideal. By quite rigid construction, the pump had always something, as this would break up relatively easily. While this is happening, but I would recommend using a flat surface as a base.

All in all, I forgive 4 stars for a great product that its function has excellently fulfilled, definitely recommended at this price:
The one star I draw from, since the product went on vacation after two or three days usage broken (but could be repaired again!) And basically works unstable. A rubberized surface on the base would at least reduce the latter feeling something.