[BPI-R4] exact dimensions of the top

Hi, i would like to order some more tops for the case of the R4 made of aluminium, so i can make holes in it and test some stuff with ventilation. But i need exact dimensions. I only have a folding rule which is absolutely not exact enough i guess. Right now i have 15.4 x 10.1 x 0.1 cm (WxLxH). Does someone have a calliper rule and measure it?