I bought a piece of 12"x12", 3/8 thick plexiglass to build a shelf. The piece which I got was slightly smaller than the stated dimensions, although not quite as much smaller as other reviewers reported. If the description had stated that the sizing is 300 mm x 300 mm, it would be more accurate. So, it was about 4 mm too small on average. It also was not perfectly square, with deviation of one side probably around a degree (as assessed with Woodpeckers precision square). Hence, in reality, the dimensions were about 1 to 2 mm different depending along which side you measure. Two sides were original and smooth, the other two were cut fairly rough. The target dimensions of my shelf were a little smaller, so I was able to cut it to exact dimensions without problems and with minimal material losses (and at least one of the four angles was perfectly square, so I started from that angle and cut along the sides which were less perfect). I used a jigsaw with a metal blade for cutting. Cutting worked out fine, except that when blade heats up it starts melting the plexiglass and it welds back behind the blade, so one has to cut slowly and a short distance at a time with blade cool-down rests in between. A rougher blade could have worked better,but I did not test it. Sanding edges was easy. The front and back surface are protected with sturdy (yet easy to remove) film. The plexiglass is totally transparent. Not cheap for what it is, but it was great that I was able to get it overnight and it met my goals. Cannot speak about durability, but I do not see a reason why it would break as load on my shelf will be small and 3/8" (thickness measures in spec, by the way) provides plenty of strength.For this price, they could have done a more accurate job of measuring and cutting and could have sanded the edges, but I am not complaining as for me it was not critical at all.