since the application of a great protector but some has pitfalls, regardless of manufacturer, it can happen from time to time that something does not work properly - there is still a speck of dust under the film, she sits slightly shifted. then you can try one of two small air bubbles to eliminate, or tried it a second time, while it is not usually better ... so are already nearly EUR 9 in the bucket. that's just not comparatively. if that would make guaranteed even with small dust particles no bubbles film, would be the price still acceptable, but that's not the case. So better another slide for half the price, which is also good, and goes wenns wrong tuts not hurt.
