The Gastec Dosi-Tube is a direct read tube which shows a colour stain to determine how much hazardous gas a worker has been in contact with over the given period.

A Gastec Dosi-Tube is a glass tube of a specific inner diametre that is filled with a diffuser and chemical reagent in parallel that enable gas to disperse at a constant rate resulting in a longer discolouration and better demarcation.

The passive Dosi-Tube can then be positioned in the worker’s breathing zone where it can be attached with a holder and collar clip (separately available: Art.No.710) and the amount of individual exposure can be measured. Stationary use is also possible for time weighted average (TWA) measurements of concentration distribution or change within a fixed environment over longer periods, such as the course of a whole day.