UNIPHOS Fumisense Pro PH3-Hi with inbuilt pump
These are paper strips impregnated with sensing chemicals by a special process for semiquantitative measurement of phosphine. The strip on exposure to PH3 gas changes its colour. The time it takes to change the colour is related to the PH3 gas concentration. They are used for checking the fumigated area after aeration and to see if the area is safe for entry. These strips can also be given to the workers as badges when they are working in/near fumigated stacks.