bobbosan, the cutout is a 57mm x 57mm rounded-corner square. The instrument face is 82mm x 82mm (for the large gauge config). The USB gauge works ok but is somewhat jittery and if configured as an F-16 ASI (as mine is) there is no way to get the Mach dial to read correctly without writing custom software with the (sparsely documented and lacking in examples) SDK. Otherwise, plug'n'play for basic use. Comes with lots of spare bits you can use for other projects.