81 in, Standards UL, CSA, ATEX, IECEx.31 in, Overall Width 4.Module, Product Type Module, Series Radius(R) BZ1, Features Face Down Positioned Smart Sensors, Module Slides Out From The Radius Base, Overall Depth 5.41 in, For Gas Type Carbon Monoxide, Hydrogen Sulfide, LEL (Pentane), Oxygen, For Use With Radius BZ1, Overall Height 3.