This thing is case for AvrUsb500v2 -- an open source Atmel AVR Programmer, stk500 V2 compatible, with USB interface (http://www.tuxgraphics.org/electronics/200705/article07052.shtml). But not only case files attached - included full set of documentation to create such AVR programmer.Why this AVR programmer attached if there are other AVR Programmers here (http://www.thingiverse.com/search?q=AVR+Programmer&sa=)? Well, main feature of this programmer is that is it fast. Much faster then USBasp or AVR910 for example (don't know about all others). Next is because this thing contain full documentation that allows to crate it, not just case (circuit, pcb layouts and case will fit each other just fine). It do not require any 3-rd party AVR programmer to program itslef (will be nice for beginners who don't have any AVR programmer). And it is also very cheap and contains only widely used components.Programmer works fine and was tested already by many people (and me also). You can use it directly with AVR Studio, CodeVision AVR or AVRDude.Thanks to Guido Socher (http://www.tuxgraphics.org/) for nice open hardware programmer. Thanks to someone with nick "Petka" for nice improved PCB layouts. Remember to print my plastic case for this programmer. And good luck to all who read till this line! :)