We recently received this review of the Draeger Pac 3500 single gas monitor for carbon monoxide: "I purchased the Draeger Pac 3500 CO single gas monitor after a recent carbon monoxide-related death in a local restaurant. As a home inspector, I often go into a home that is vacant and turn on the heating system. If the levels of CO rise to a dangerous level, I might not know until it was too late. "The Draeger unit is compact and easy to use. I like the digital readout so I don't have to wait until an alarm sounds to know if there is problem. I like the user-replaceable battery so you don't have to send it back to the factory. The only down side is the belt clip is too aggressive (tight and serrated) to use on a regular belt without damaging the belt. I rate the Draeger Pac 3500 CO single gas monitor a 4 out of 5 because of the belt clip." Bruce Weller - Eagle Eye Professional Home Inspection It's an informative review, and highlights important points about CO detection from someone with over 30 years of experience. We're willing to accept a clip that's too tight on a gas detector far more than one that's too loose. We appreciate the reviews from the folks using these instruments in the field to keep themselves safe.