The Model HRMS-01 and HRMS-02 is a compete system for mounting a Dissolved Oxygen (DO) sensor Model 499ADO to a handrail. It consists of a swivel/pivot bracket, and maintenance bracket. The unique swivel/pivot pipe clamp assembly allows easy sensor removal from the process by swinging the pipe boom up and over to the handrail for maintenance. The sensor maintenance bracket allows the pipe boom to be supported in a fixed position while performing maintenance and calibration on the sensor.