Flush Mount Pressure Transmitters - SmartLine ST700 Part of the SmartLine® family of products, the STG73P is a gauge pressure transmitter with a flush mounted diaphragm. Installed using a 1” sleeve welded to the process piping the diaphragm face may be situated flush with the process piping wall. Typically applied to applications such as head boxes in pulp and paper mills, flush mounting eliminates the possibility of clogging. In addition, the transmitter mounting facilitates