With this simple device you can make a plastic bag of any size. The technology is very simple: between two of the straps are clamped by the two segments of the film so that the region made in strips about 1 mm. Podpravit them throughout the length of a match and will get smooth and durable seam, not inferior to factory. My only comment is that if the film is thick enough, you should increase the width of the protruding stripes up to 2 or even to 3 mm, but not more, otherwise the seam .get ugly and fragile.
A. MATETSKIY, Jelgava