The SINA One Way H is a black/red gateway. It consists of a data diode and two peripheral proxies used as transfer computers. The SINA One Way H allows data transfers in one direction only from a public or lower-level "black" source network to a higher-level "red" target network. The system enables, for instance, the transfer of public data found on the Internet to a SECRET network.

The transfer protocol running between the two proxies works with automatic error detection and error correction.

Unlike the SINA Box, the SINA One Way H is not a cryptographic component. The complete implementation of unidirectional data transfer by means of the hardware based data diode was critical for SECRET approval of the system. This security functionality ensures that no information leaves the "red" target network in the wrong direction without being noticed.