MSA Chemgard - Figure 2-4. XP Unit Mounting Dimensions

Chemgard Infrared Gas Monitor
Section 2, Installation and Setup
2-5
NOTE: The XP version has not been tested by UL for performance.
Internal grounding terminal shall be used as the equipment grounding means and
the external ground terminal is only a supplemental bonding connection where
local authorities permit or require such a connection.
Figure 2-4. XP Unit Mounting Dimensions