The device will transfer data between two computers. The hardware must be secure, no possibility for direct copy from computer A to computer B and backward. The first computer store data on flash 1. The microcontroller copy data from flash 1 to flash 2, the second computer copy from flash 2 to local directory. Both computers are with Linux. The product is a printed circuit board with two USB connectors, two flash memory chips, one microcontroller. The data transfer is few times per day at given clock time.